When a small summoner summons a medium Eidolon and fuses with it, what size is the resulting combination?

The eidolon must be at least the same size as the synthesist.


Your size increases to match your Eidolon's

While there is no rule specifically mentioning a size increase on neither the Synthesist's Eidolon ability, nor the Summoner's Eidolon base ability, when discussing the several FAQ requests about the synthesists, Seak K Reynolds (back then, a Paizo's Developer) did give us an example of what happens when a medium-sized summoner merges with a large-sized eidolon:

I've talked to Jason and updated the FAQ about share spells. To sum up: yes, a regular summoner is able to cast humanoid-only spells on his eidolon (duh); yes, a synthesist can too because it doesn't alter share spells.

There is a bit of weirdness about the synthesist and enlarge person that Jason wants to think about for a bit because of the "eidolon must be at least the same size as the synthesist" rule. Basically, if you're Medium and the eidolon is Medium, should it be assumed that the spell affects you "both," or is it a weird case where the summoner "outgrows" the Medium eidolon. Likewise, if you're Medium and the eidolon is Large, you already have the Large benefits, so turning into a Large summoner inside a Large eidolon-shell shouldn't have any effect.

Anyway, he's going to let that "roll around in the old rock tumbler," as he puts it.

| improve this answer | |
  • \$\begingroup\$ If I used Evolution surge greater to gain the large evolution after fusing, would that change my size? Im asking because you get to benefit from the evolutions and size is an evolution. \$\endgroup\$ – Fering Sep 23 '17 at 3:55
  • \$\begingroup\$ All I see is that enlarge person will work on the Eidolon while fused. In this case since you are one and the same both of you should become larger. I see nothing in the FAQ about the size evolutions. \$\endgroup\$ – Fering Sep 23 '17 at 4:09
  • \$\begingroup\$ @Fering the FAQ i linked had a note at the end about size: "FAQ pending about size-changing magic and a synthesist (because of the limitation of "the eidolon must be at least the same size as the synthesist" rule)." \$\endgroup\$ – ShadowKras Sep 23 '17 at 4:12
  • \$\begingroup\$ Because that question was literally skipped over during that series of FAQs, the author of that thread did ask what happens when a medium summoner merged with a large-sized eidolon, but wasn't officially answered. \$\endgroup\$ – ShadowKras Sep 23 '17 at 4:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.