Temporary EIDs (cleared to 0/false each chapter unless otherwise stated)
0 (0x0) : Always false
1 (0x1) : Free (conventionally used for boss quote)
2 (0x2) : Free (conventionally used for boss death-quote)
3 (0x3) : Chapter win flag
4 (0x4) : In-Chapter music change flag
5 (0x5) : Free
6 (0x6) : Rout flag
7-40 (0x7-0x28) : Free
41-63(0x29-0x3F) : Free, cleared on suspend/resume but not each chapter
64-100(0x40-0x64) : Unusable (and volatile)
Permanent EIDs (persist throughout gameplay)
101 (0x65) : used with Game Over
102 (0x66) : makes objective window disappear when true
103-112 (0x67-0x70) : each unlocks a Creature Campaign unit when set
113-119 (0x71-0x77) : repurposable, set when clearing chapters 9-15 on either route
120-126 (0x78-0x7E) : free
127-129 (0x7F-0x81) : used relating to Triangle Attack dialogue
130 (0x82) : used with DK/Formortiis battle music changing
131 (0x83) : free
132 (0x84) : hides any info icons over map sprites when on
133 (0x85) : used in FE8J version, screen for evaluating the capture of unused code
134 (0x86) : repurposable, used when Amelia dies so she doesn’t reappear
135 (0x87) : repurposable, used with trade menu tutorial
136 (0x88) : used with world map. If next chapter is 0x6 and this flag is set, skip chapter intro.
137 (0x89) : used first time world map is loaded
138 (0x8A) : used with world map post-Castle Frelia
139-175 (0x8B-0xAF) : probably free
176-178 (0xB0-0xB2) : free
179 (0xB3) : used to determine sorting in FE8U version of guide
180-235 (0xB4-0xEB) : Used by Guide (see [FE8] "Help" Command & Permanent Event IDs)
236-239 (0xEC-0xEF) : free
240-295 (0xF0-0x127) : Used to mark guide entries as read
296-300 (0x128-0x12C) : free
Compiled from various sources (FEBuilder doc, FEU topics and discord notes) and put all into one place for convenience. Feel free to correct me on anything I may have missed (and thanks!).
eid 3 is more generally the “win” eid. If the game needs to know if the current chapter was won it will check for this eid. For example, the game won’t save the chapter time/turn counts when you end it if this eid isn’t set (which is why in some hacks such as VBA the turn count roll at the end of the game skips many chapters).
Somewhat related note: the EA stdlib doesn’t really account for that and for example defines DefeatBoss as AFEV 0 <scEnding> 2; while vanilla events use AFEV 3 <scEnding> 2 (and same deal for DefeatAll); so if you use EA for events be careful! (stdlib repo when)
130 (0x82) : free
Not really. I think it has something to do with DK/Fomortiis battle animations. (checked/set by FE8U:08084634/FE8U:08084628). I wouldn’t recommend (re)using it if you plan on using DK anims.
135 (0x87) : free
I think it has to do with the trade menu tutorial (hardcoded unset at FE8U:0802E06C). It’s still probably safe to use in hacks.
I had no idea this was a thing; thank you! I’m very happy that I will no longer have to set aside extra character slots to use boss characters in cutscenes.
Addenum: It hides all of those sorts of sprites, not just boss icons. Status signs (z’s from sleep, x’d box from silence, yellow bubble thingy from berserk), hp bars, effectiveness icons, the works.
Not all of these EIDs are actually free, plus we can go a bit further
Global EIDs are stored from 0x3005250 to 0x3005268, so in total there are 300 valid EID values (including the volatile ones)
236-239 (0xEC-0xEF) are free
240-295 (0xF0-0x127) are flags used for marking guide entries as read (appear to do nothing if the corresponding flags for guide entries are not also set, which is probably why they’re labelled as free/unknown in the previous doc)
296-300 (0x128-0x12C) are free
Flag 0xB3 is used to press the SELECT button on the Guide screen to determine if it is sorting.
This flag is used in 0x080CF164 (FE8U).
Flag 0x85 is used only with FE8J.
Probably, I think that it is the screen for evaluating the capture of Unused code.
This flag is used in 0x080A4358(FE8J).
Straightened up some wording instead of “refresh” after some dialogue in the Discord (#general, Jun 22, 2020, 2:15CST). Programming terminology isn’t my forte so I appreciate the correction.