Rare enemy appearance chances?

[Chaos Rappy]

So, just want to ask you guys your opinions of what you believe the chances of finding a rare variant of the enemies that appear in each area, with supporting evidence on your kill counts for each. I'll start with mine, and once we get a bunch of data collected, maybe we can figure out what the closest approximate true value for each rare enemies' rarities are!

I will also be including Vespao in this list, due to its "uncommonness" of appearance, as well as only one appearing at a time when it DOES appear, making it share a rarity rate of appearance close to some of the "rare" enemies in this list as well, such as the -veils.

Tormatible: 3%
Grimble kills: 2001
Tormatible kills: 67

Blaze Helion: 5-7%
Helion kills: 1157
Blaze Helion kills: 78

Vespao: 10%
Hypao kills: 2519
Vespao kills: 274

Pelcatobur: 4-5%
Pelcatraz kills: 820
Pelcatobur kills: 34

Usanimere: 1% <rarest enemy by far>
Usanny kills: 3289
Usanimere kills: 32

Hildegigas: 5%
Hildegao kills: 679
Hildeghana kills: 289
Hildegigas kills: 46

Goldix: 4-5%
Bolix kills: 5539
Goldix kills: 234

Azherowa-B2: 1-2% <almost as rare as Usanimere! :O>
Izhirak-S6 kills: 5195
Azherowa-B2 kills: 87

Frunaked: 3-5%
Fruoutang kills: 2663
Frunaked kills: 92

Rohcrysta: 5%
Rohjade kills: 809
Rohcrysta kills: 41

Arkzein R: 3-5%
Arkzein kills: 1376
Arkzein R kills: 50

Eulidveil: 8-10%
Eulid kills: 3918
Eulidveil kills: 298

Euladaveil: 8-10%
Eulada kills: 3137
Euladaveil kills: 281

Phobos Dyna: 5%
Phobos kills: 1441
Phobos Dyna kills: 75

Zaphobos Dyna: 3-5%
Zaphobos kills: 1139
Zaphobos Dyna kills: 39

Which leads to this list of which enemies are rarest, according to my games' combined kill rate percentages, listed by lowest % to highest %:

Usanimere: 1%
Azherowa-B2: ~2%
Grimble: ~3%
Zaphobos Dyna: ~3%
Frunaked: ~3-4%
Arkzein R: ~4-5%
Peclatobur: ~4-5%
Goldix: ~4-5%
Phobos Dyna: ~5%
Hildegigas: 5%
Rohcrysta: 5%
Blaze Helion: ~6%
Euladaveil: ~9%
Eulidveil: ~9%
Vespao: ~10%

Feel free to add your own kill counts to the mix as well to help my experimentations and results!

[Norco]

Interesting, I will get around to doing this later. My numbers will be far from as impressive though xD

[Mustache]

Tormatible: 4%
Grimble kills: 2123
Tormatible kills: 87

Blaze Helion: 6%
Helion kills: 1036
Blaze Helion kills: 59

Vespao: 10%
Hypao kills: 2116
Vespao kills: 212

Pelcatobur: 5%
Pelcatraz kills: 650
Pelcatobur kills: 30

Usanimere: 1%
Usanny kills: 3284
Usanimere kills: 46

Hildegigas: 5%
Hildegao kills: 826
Hildeghana kills: 317
Hildegigas kills: 53

Goldix: 5%
Bolix kills: 2274
Goldix kills: 116

Azherowa-B2: 2%
Izhirak-S6 kills: 2093
Azherowa-B2 kills: 45

Frunaked: 3%
Fruoutang kills: 1160
Frunaked kills: 30

Rohcrysta: 4%
Rohjade kills: 739
Rohcrysta kills: 33

Arkzein R: 5%
Arkzein kills: 599
Arkzein R kills: 27

Eulidveil: 6%
Eulid kills: 1734
Eulidveil kills: 111

Euladaveil: 8%
Eulada kills: 1502
Euladaveil kills: 116

Phobos Dyna: 4%
Phobos kills: 787
Phobos Dyna kills: 31

Zaphobos Dyna: 3%
Zaphobos kills: 683
Zaphobos Dyna kills: 19

[Nick O'Demus]

I'm using the total kills from both my carts:

Tormatible: 4.1%
Grimble kills: 1977
Tormatible kills: 81

Blaze Helion: 3.9%
Helion kills: 1114
Blaze Helion kills: 44

Vespao: 10.1%
Hypao kills: 3563
Vespao kills: 361

Pelcatobur: 3.5%
Pelcatraz kills: 1135
Pelcatobur kills: 40

Usanimere: 1.8%
Usanny kills: 5440
Usanimere kills: 98

Hildegigas: 5.5%
Hildegao kills: 1086
Hildeghana kills: 463
Hildegigas kills: 85

Goldix: 5.5%
Bolix kills: 2515
Goldix kills: 138

Azherowa-B2: 1.9%
Izhirak-S6 kills: 2365
Azherowa-B2 kills: 45

Frunaked: 3.4%
Fruoutang kills: 1352
Frunaked kills: 46

Rohcrysta: 3.5%
Rohjade kills: 1484
Rohcrysta kills: 52

Arkzein R: 5.5%
Arkzein kills: 1118
Arkzein R kills: 61

Eulidveil: 6.3%
Eulid kills: 1458
Eulidveil kills: 92

Euladaveil: 6.9%
Eulada kills: 1240
Euladaveil kills: 86

Phobos Dyna: 3.2%
Phobos kills: 907
Phobos Dyna kills: 29

Zaphobos Dyna: 2.7%
Zaphobos kills: 731
Zaphobos Dyna kills: 20

[Chaos Rappy]

Awesome additions guys. Only helps to prove my theory that Usanimere is still pretty much the rarest enemy in the game, and interestingly not that far ahead of the Azherowa-B2... wonder why the Azherowa's don't get the "special enemy appearance" theme played when they appear, like the Rappies, Boomas, and Usanimeres, when they're just about as rare? <.<

[Nick O'Demus]

Adding a few more, just because:

Since Vespao was listed:
Akorse: 10.8%
Korse kills: 7472
Akorse kills: 806

Compared to total enemy encounters:
Total kills: 85,191

Rappies: 0.22%
Rappy kills: 93
Ar Rappy kills: 50
Rab Rappy kills: 44

Boomas: 0.33%
Booma Origin kills: 157
Gigobooma Origin kills: 122

[Chaos Rappy]

Oh, those numbers are rather unnecessary, really... Akorse has a low number usually because while it commonly appears, it only ever appears one at a time. Unlike the Vespao, note I said "commonly appears"... which I wish wasn't true, since Vespao does have rare drops. <.<

As for the Rappies and Boomas, their appearance rate has already been determined from reliable sources, so I left them out with good reason. They both have an approximate 5% chance of appearing in any stage, the chances involved being higher or lower if you actually fulfill the requirement for their chance of appearing to matter, like going to the dead-ends / crossroads for Rappies, or backtracking from a dead-end for Boomas... :/

[Eclipse5632]

Are there ever two Vespaos in the same room? I thought there was usually only one.

[Chaos Rappy]

Nope. Vespao only either appears with three other Hypaos or with a bunch of Pomarr's, I think...

[DoctorShanks]

Vespao, Eulidveil, and Euladaveil aren't really rare, but uncommon.

Tormatible: 4.4%
Grimble kills: 2042
Tormatible kills: 90

Blaze Helion: 9.1%
Helion kills: 1134
Blaze Helion kills: 103

Vespao: 7.2%
Hypao kills: 4527
Vespao kills: 328

Pelcatobur: 7.8%
Pelcatraz kills: 1176
Pelcatobur kills: 92

Usanimere: 0.9%
Usanny kills: 7786
Usanimere kills: 72

Hildegigas: 3.7%
Hildegao kills: 1911
Hildeghana kills: 741
Hildegigas kills: 97

Goldix: 4.5%
Bolix kills: 3450
Goldix kills: 154

Azherowa-B2: 2.2% (=U)
Izhirak-S6 kills: 3220
Azherowa-B2 kills: 71

Frunaked: 3.5%
Fruoutang kills: 1758
Frunaked kills: 62

Rohcrysta: 5.1%
Rohjade kills: 2173
Rohcrysta kills: 110

Arkzein R: 3%
Arkzein kills: 1149
Arkzein R kills: 34

Eulidveil: 8.8%
Eulid kills: 3317
Eulidveil kills: 294

Euladaveil: 8.1%
Eulada kills: 2701
Euladaveil kills: 219

Phobos Dyna: 5.3%
Phobos kills: 1309
Phobos Dyna kills: 70

Zaphobos Dyna: 4.3%
Zaphobos kills: 1000
Zaphobos Dyna kills: 43

Azherowa is one of the rarest because whenever he spawns, he spawns alone, and the Izharaks can spawn in pairs. Tormitable spawns in groups of 3 (or side by side with a Blaze Helion) for example. Usanimere has the lowest count because of the abundance of the Usannies. Hildegigas would have been the rarest if it wasn't for the final boss room having a high chance to spawn it. Rohcrystas are pretty common in my experiences.