New build is getting close to being done! Here’s a few screenshots related to enemy summoners!
Ludoc is the first summoner you’re likely to meet…and yep, if Headless didn’t spawn earlier in the game, you may see him as one of Ludoc’s pals. As you can see, just like you, enemy summoners will unsummon and summon their allies as needed. And of course, no recruiting their allies (at least, not while the summoner is still alive…)
…releasing all of the demons at once, though with various Mind-flavor bad status. However, at this point you can recruit them. Enemy summoners customize their demons just like you do, so they may have some very powerful allies you can snag if you play your cards right.