Hello!
Thank you for making a bug report!
Lyris is in fact correct. Pain Lanius requires you to take damage apart of it’s effect. Since 0 is the lowest stat on Raider’s wing, you cannot use it as a legal target to summon Pain Lanius with, since taking 0 damage would not be “taking damage”.
You can see that I also had this misunderstanding a few months ago when I reported a bug on the same thing: Raidraptor interaction - Pain Lanius & Raider's Wing
This is functioning as intended and thread will be closed in the next 24 hours.
Once again, thank you for making a bug report! If you happen to find anything else you believe to be a bug, please feel free to report it and we will look into it!
Thank you for helping make Omega the best we can!