diff --git a/code/__DEFINES/flags.dm b/code/__DEFINES/flags.dm
index 8b3e74b96e..cb8a2ad2ca 100644
--- a/code/__DEFINES/flags.dm
+++ b/code/__DEFINES/flags.dm
@@ -6,6 +6,10 @@
 
 GLOBAL_LIST_INIT(bitflags, list(1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768))
 
+// for /datum/var/datum_flags
+#define DF_USE_TAG 1
+#define DF_VAR_EDITED 2
+
 //FLAGS BITMASK
 #define STOPSPRESSUREDMAGE_1 1	//This flag is used on the flags_1 variable for SUIT and HEAD items which stop pressure damage. Note that the flag 1 was previous used as ONBACK, so it is possible for some code to use (flags & 1) when checking if something can be put on your back. Replace this code with (inv_flags & SLOT_BACK) if you see it anywhere
 //To successfully stop you taking all pressure damage you must have both a suit and head item with this flag.
diff --git a/code/__HELPERS/unsorted.dm b/code/__HELPERS/unsorted.dm
index 6256fedaea..ad52e5b340 100644
--- a/code/__HELPERS/unsorted.dm
+++ b/code/__HELPERS/unsorted.dm
@@ -1489,14 +1489,14 @@ GLOBAL_DATUM_INIT(dview_mob, /mob/dview, new)
 
 // \ref behaviour got changed in 512 so this is necesary to replicate old behaviour.
 // If it ever becomes necesary to get a more performant REF(), this lies here in wait
-// #define REF(thing) (thing && istype(thing, /datum) && thing:use_tag && thing:tag ? "[thing:tag]" : "\ref[thing]")
+// #define REF(thing) (thing && istype(thing, /datum) && (thing:datum_flags & DF_USE_TAG) && thing:tag ? "[thing:tag]" : "\ref[thing]")
 /proc/REF(input)
 	if(istype(input, /datum))
 		var/datum/thing = input
-		if(thing.use_tag)
+		if(thing.datum_flags & DF_USE_TAG)
 			if(!thing.tag)
-				stack_trace("A ref was requested of an object with use_tag set but no tag: [thing]")
-				thing.use_tag = FALSE
+				stack_trace("A ref was requested of an object with DF_USE_TAG set but no tag: [thing]")
+				thing.datum_flags &= ~DF_USE_TAG
 			else
 				return "\[[url_encode(thing.tag)]\]"
 	return "\ref[input]"
diff --git a/code/controllers/configuration/config_entry.dm b/code/controllers/configuration/config_entry.dm
index d1be661f6a..87112f0001 100644
--- a/code/controllers/configuration/config_entry.dm
+++ b/code/controllers/configuration/config_entry.dm
@@ -43,7 +43,7 @@
 			return FALSE
 		. = ValidateAndSet("[var_value]")
 		if(.)
-			var_edited = TRUE
+			datum_flags |= DF_VAR_EDITED
 		return
 	if(var_name in banned_edits)
 		return FALSE
@@ -114,7 +114,7 @@
 	var/temp = text2num(trim(str_val))
 	if(!isnull(temp))
 		value = CLAMP(integer ? round(temp) : temp, min_val, max_val)
-		if(value != temp && !var_edited)
+		if(value != temp && !(datum_flags & DF_VAR_EDITED))
 			log_config("Changing [name] from [temp] to [value]!")
 		return TRUE
 	return FALSE
diff --git a/code/datums/callback.dm b/code/datums/callback.dm
index 5566137189..6e92d41c6d 100644
--- a/code/datums/callback.dm
+++ b/code/datums/callback.dm
@@ -89,7 +89,7 @@
 			calling_arguments = calling_arguments + args //not += so that it creates a new list so the arguments list stays clean
 		else
 			calling_arguments = args
-	if(var_edited)
+	if(datum_flags & DF_VAR_EDITED)
 		return WrapAdminProcCall(object, delegate, calling_arguments)
 	if (object == GLOBAL_PROC)
 		return call(delegate)(arglist(calling_arguments))
@@ -115,7 +115,7 @@
 			calling_arguments = calling_arguments + args //not += so that it creates a new list so the arguments list stays clean
 		else
 			calling_arguments = args
-	if(var_edited)
+	if(datum_flags & DF_VAR_EDITED)
 		return WrapAdminProcCall(object, delegate, calling_arguments)
 	if (object == GLOBAL_PROC)
 		return call(delegate)(arglist(calling_arguments))
diff --git a/code/datums/components/forensics.dm b/code/datums/components/forensics.dm
index 76baa057cc..417525ab08 100644
--- a/code/datums/components/forensics.dm
+++ b/code/datums/components/forensics.dm
@@ -139,7 +139,8 @@
 		if(laststamppos)
 			LAZYSET(hiddenprints, M.key, copytext(hiddenprints[M.key], 1, laststamppos))
 		hiddenprints[M.key] += " Last: [M.real_name]\[[current_time]\][hasgloves]. Ckey: [M.ckey]"	//made sure to be existing by if(!LAZYACCESS);else
-	parent.fingerprintslast = M.ckey
+	var/atom/A = parent
+	A.fingerprintslast = M.ckey
 	return TRUE
 
 /datum/component/forensics/proc/add_blood_DNA(list/dna)		//list(dna_enzymes = type)
diff --git a/code/datums/datum.dm b/code/datums/datum.dm
index 6a3ad57878..d07890275d 100644
--- a/code/datums/datum.dm
+++ b/code/datums/datum.dm
@@ -1,14 +1,13 @@
 /datum
-    var/gc_destroyed //Time when this object was destroyed.
-    var/list/active_timers  //for SStimer
-    var/list/datum_components //for /datum/components
-    var/ui_screen = "home"  //for tgui
-    var/use_tag = FALSE
-    var/datum/weakref/weak_reference
+	var/gc_destroyed //Time when this object was destroyed.
+	var/list/active_timers  //for SStimer
+	var/list/datum_components //for /datum/components
+	var/datum_flags = NONE
+	var/datum/weakref/weak_reference
 
 #ifdef TESTING
-    var/running_find_references
-    var/last_find_references = 0
+	var/running_find_references
+	var/last_find_references = 0
 #endif
 
 // Default implementation of clean-up code.
@@ -38,10 +37,4 @@
 			qdel(C, FALSE, TRUE)
 		dc.Cut()
 
-	var/list/focusers = src.focusers
-	if(focusers)
-		for(var/i in 1 to focusers.len)
-			var/mob/M = focusers[i]
-			M.set_focus(M)
-
 	return QDEL_HINT_QUEUE
diff --git a/code/datums/datumvars.dm b/code/datums/datumvars.dm
index 8f8fa8f1f0..672ec3a58b 100644
--- a/code/datums/datumvars.dm
+++ b/code/datums/datumvars.dm
@@ -1,18 +1,11 @@
-/datum
-	var/var_edited = FALSE //Warrenty void if seal is broken
-	var/fingerprintslast = null
-
 /datum/proc/can_vv_get(var_name)
 	return TRUE
 
 /datum/proc/vv_edit_var(var_name, var_value) //called whenever a var is edited
-	switch(var_name)
-		if ("vars")
-			return FALSE
-		if ("var_edited")
-			return FALSE
-	var_edited = TRUE
+	if(var_name == NAMEOF(src, vars))
+		return FALSE
 	vars[var_name] = var_value
+	datum_flags |= DF_VAR_EDITED
 
 /datum/proc/vv_get_var(var_name)
 	switch(var_name)
@@ -109,7 +102,7 @@
 	if(holder && holder.marked_datum && holder.marked_datum == D)
 		marked = "<br><font size='1' color='red'><b>Marked Object</b></font>"
 	var/varedited_line = ""
-	if(!islist && D.var_edited)
+	if(!islist && (D.datum_flags & DF_VAR_EDITED))
 		varedited_line = "<br><font size='1' color='red'><b>Var Edited</b></font>"
 
 	var/list/dropdownoptions = list()
diff --git a/code/game/atoms.dm b/code/game/atoms.dm
index 6645ffe37a..0643918b3d 100644
--- a/code/game/atoms.dm
+++ b/code/game/atoms.dm
@@ -26,13 +26,14 @@
 
 	var/datum/proximity_monitor/proximity_monitor
 	var/buckle_message_cooldown = 0
+	var/fingerprintslast
 
 /atom/New(loc, ...)
 	//atom creation method that preloads variables at creation
 	if(GLOB.use_preloader && (src.type == GLOB._preloader.target_path))//in case the instanciated atom is creating other atoms in New()
 		GLOB._preloader.load(src)
 
-	if(use_tag)
+	if(datum_flags & DF_USE_TAG)
 		GenerateTag()
 
 	var/do_initialize = SSatoms.initialized
diff --git a/code/game/gamemodes/nuclear/nuclearbomb.dm b/code/game/gamemodes/nuclear/nuclearbomb.dm
index aa7e7d0178..37b87ce6de 100644
--- a/code/game/gamemodes/nuclear/nuclearbomb.dm
+++ b/code/game/gamemodes/nuclear/nuclearbomb.dm
@@ -79,14 +79,14 @@
 	anchored = TRUE //stops it being moved
 
 /obj/machinery/nuclearbomb/syndicate
-	use_tag = TRUE
+	datum_flags = DF_USE_TAG
 	//ui_style = "syndicate" // actually the nuke op bomb is a stole nt bomb
 
 /obj/machinery/nuclearbomb/syndicate/GenerateTag()
 	var/obj/machinery/nuclearbomb/existing = locate("syndienuke") in GLOB.nuke_list
 	if(existing)
 		stack_trace("Attempted to spawn a syndicate nuke while one already exists at [COORD(existing.loc)]")
-		use_tag = FALSE
+		datum_flags &= ~DF_USE_TAG
 		return
 	tag = "syndienuke"
 
diff --git a/code/modules/admin/verbs/modifyvariables.dm b/code/modules/admin/verbs/modifyvariables.dm
index e4c86315b5..da448b8eca 100644
--- a/code/modules/admin/verbs/modifyvariables.dm
+++ b/code/modules/admin/verbs/modifyvariables.dm
@@ -1,4 +1,4 @@
-GLOBAL_LIST_INIT(VVlocked, list("vars", "var_edited", "client", "virus", "viruses", "cuffed", "last_eaten", "unlock_content", "force_ending"))
+GLOBAL_LIST_INIT(VVlocked, list("vars", "datum_flags", "client", "virus", "viruses", "cuffed", "last_eaten", "unlock_content", "force_ending"))
 GLOBAL_PROTECT(VVlocked)
 GLOBAL_LIST_INIT(VVicon_edit_lock, list("icon", "icon_state", "overlays", "underlays", "resize"))
 GLOBAL_PROTECT(VVicon_edit_lock)
@@ -214,7 +214,7 @@ GLOBAL_PROTECT(VVpixelmovement)
 				return
 			.["type"] = type
 			var/atom/newguy = new type()
-			newguy.var_edited = TRUE
+			newguy.datum_flags |= DF_VAR_EDITED
 			.["value"] = newguy
 
 		if (VV_NEW_DATUM)
@@ -224,7 +224,7 @@ GLOBAL_PROTECT(VVpixelmovement)
 				return
 			.["type"] = type
 			var/datum/newguy = new type()
-			newguy.var_edited = TRUE
+			newguy.datum_flags |= DF_VAR_EDITED
 			.["value"] = newguy
 
 		if (VV_NEW_TYPE)
@@ -243,7 +243,7 @@ GLOBAL_PROTECT(VVpixelmovement)
 			.["type"] = type
 			var/datum/newguy = new type()
 			if(istype(newguy))
-				newguy.var_edited = TRUE
+				newguy.datum_flags |= DF_VAR_EDITED
 			.["value"] = newguy
 
 
diff --git a/code/modules/jobs/job_exp.dm b/code/modules/jobs/job_exp.dm
index 9bbb753de6..534e530e17 100644
--- a/code/modules/jobs/job_exp.dm
+++ b/code/modules/jobs/job_exp.dm
@@ -228,7 +228,7 @@ GLOBAL_PROTECT(exp_to_update)
 							play_records[role] += minutes
 							if(announce_changes)
 								to_chat(mob,"<span class='notice'>You got: [minutes] [role] EXP!</span>")
-				if(mob.mind.special_role && !mob.mind.var_edited)
+				if(mob.mind.special_role && !(mob.mind.datum_flags & DF_VAR_EDITED))
 					var/trackedrole = mob.mind.special_role
 					play_records[trackedrole] += minutes
 					if(announce_changes)
diff --git a/code/modules/keybindings/focus.dm b/code/modules/keybindings/focus.dm
index 9d3e44f059..205b293e9a 100644
--- a/code/modules/keybindings/focus.dm
+++ b/code/modules/keybindings/focus.dm
@@ -1,20 +1,8 @@
-/datum
-	var/list/focusers //Only initialized when needed. Contains a list of mobs focusing on this.
-
 /mob
 	var/datum/focus //What receives our keyboard inputs. src by default
 
 /mob/proc/set_focus(datum/new_focus)
 	if(focus == new_focus)
 		return
-
-	if(new_focus)
-		if(!new_focus.focusers) //Set up the new focus
-			new_focus.focusers = list()
-		new_focus.focusers += src
-
-	if(focus)
-		focus.focusers -= src //Tell the old focus we're done with it
-
 	focus = new_focus
-	reset_perspective(focus) //Maybe this should be done manually? You figure it out, reader
\ No newline at end of file
+	reset_perspective(focus) //Maybe this should be done manually? You figure it out, reader
diff --git a/code/modules/mob/mob.dm b/code/modules/mob/mob.dm
index 7387fe57a5..5bc054951b 100644
--- a/code/modules/mob/mob.dm
+++ b/code/modules/mob/mob.dm
@@ -174,8 +174,7 @@
 	return 0
 
 /mob/proc/Life()
-	set waitfor = 0
-	return
+	set waitfor = FALSE
 
 /mob/proc/get_item_by_slot(slot_id)
 	return null
diff --git a/code/modules/mob/mob_defines.dm b/code/modules/mob/mob_defines.dm
index d7bba73ce7..536ee125e0 100644
--- a/code/modules/mob/mob_defines.dm
+++ b/code/modules/mob/mob_defines.dm
@@ -1,11 +1,11 @@
 /mob
+	datum_flags = DF_USE_TAG
 	density = TRUE
 	layer = MOB_LAYER
 	animate_movement = 2
 	flags_1 = HEAR_1
 	hud_possible = list(ANTAG_HUD)
 	pressure_resistance = 8
-	use_tag = TRUE
 	var/lighting_alpha = LIGHTING_PLANE_ALPHA_VISIBLE
 	var/datum/mind/mind
 	var/list/datum/action/actions = list()
diff --git a/code/modules/tgui/tgui.dm b/code/modules/tgui/tgui.dm
index b1275cf00f..bb545547f9 100644
--- a/code/modules/tgui/tgui.dm
+++ b/code/modules/tgui/tgui.dm
@@ -35,6 +35,7 @@
 	var/list/datum/tgui/children = list() // Children of this UI.
 	var/titlebar = TRUE
 	var/custom_browser_id = FALSE
+	var/ui_screen = "home"
 
  /**
   * public
@@ -216,7 +217,7 @@
 	var/list/config_data = list(
 			"title"     = title,
 			"status"    = status,
-			"screen"	= src_object.ui_screen,
+			"screen"	= ui_screen,
 			"style"     = style,
 			"interface" = interface,
 			"fancy"     = user.client.prefs.tgui_fancy,
@@ -277,7 +278,7 @@
 			initialized = TRUE
 		if("tgui:view")
 			if(params["screen"])
-				src_object.ui_screen = params["screen"]
+				ui_screen = params["screen"]
 			SStgui.update_uis(src_object)
 		if("tgui:link")
 			user << link(params["url"])