Hm… historically I seem to remember summons always being forced to max level (15) in Arena, regardless of what level they would be under normal summoning rules. I haven’t used a summoner in Arena since the revamp, and haven’t played arena regularly in a really long time regardless and when I did there wasn’t much summoning going on, but the times my opponent had them they seemed to have level 15 stats. I didn’t inspect further because this was expected due to what I understood to be the “Arena rule”.
Doing a bit of research, this was on the “known issues” list at one point a long time ago and possibly considered a bug:
But I remember this being a thing years after this point (again, could be wrong here, this wasn’t my focus), and I can’t find the point at which this “bug” was reported to be fixed in any patch notes.
There have been a number of other summon(/transform) bugs over the years in arena, including periods where transformed troops would check the players actual collection (baby dragon getting fully traited level 20 troops) or stuff being summoned in that said it was a certain level but had stats for a different level, which I’ve seen reports on over the years and unsure what the timetable on these bugs being active was (I know the Baby Dragon one was fixed because I personally experienced that one while it was active, after the fix was active, and recently after the arena revamp).
So, if you cast this troop in an arena battle would it be intended level 1 summon but is actually level 15? Intended level 15 but is actually level 1? Intended level whatever but it is actually correct? I have no idea at this point.