I got both of them and I’m unsure on which to level. My main focus is titan battles, but I have to mention I don’t have a debuffer yet (I have only 3* debuffers).
I would probably say Caedmon with that information. The debuffer can really help.
Caed was a staple for me until I pulled Lianna from TC20. I still use him often for farming and titans and hes the druid with my emblems so he is worth it.
Both are great 4* green heroes with almost identical stats and special damage.
If you dont have another dispeller and feel like you need a one badly, then Caed. But since you’ve said your main focus is titan battles i’d pick Peters since his special delays that titan special attack, which is great and buys some time. You can always ascend Caed later since he’s a great green to have around.
Btw, a debuffer is one that lowers or reduce defenses or resistances to a certain color.
A dispeller is one that removes positive effects from enemies heroes or abilities that can harm your heroes while attacking like perfect riposte. [just remember when you use dispellers like Sonya or Caed to avoid direct hits on those, because first they do the damage and only afterwards they remove the effect - not to be confused with what Kageburado does tho, because he first dispel then do the damage].
going with Peters first
I have both and for me it is Peters hands down. Caed’s ability is also replicated with Sonya and to a similar extent Kageburrito. You can also dispel with other effects (e.g. Gandalf and Sabina’s heal). Peter’s ability to silence for 3 turns is unique and being able to delay a special from going off against Titans is invaluable since the time delay could be the difference between another attack/ cascade firing before time runs out.