Well, when I decided to use the succubus guardian as main character, which is possible by changing its alternate art just like how druid/creator do and use the correct order of sacrificing characters via soul drain, which if done right, can result in a busted character that surpasses the other 2 guardian main characters stat wise and having easier difficulty, heck, even the giant dragon becomes a joke due to its lack of flexibility for magic abilities or fast enough scaling in other fields, but a all-rounder with randomized first spell, plenty of global skills, backstab and ghost beam is truly a skill combo that can rival god form at max power, if not outright surpass it...Usually guardians are an late game thing due to their heavy requirements to get their best potential, but a main character that negates their main weakness and can actually almost maxed gene spirits in spite of lacking spirit skills let alone a skill tree is truly terrifying...Sure, you do have to work for that massive advantage like getting a gem girl as soon as possible, which you already can do by having stone element and rapidly evolving stuff to get characters you need, but of course the first sacrifice is one of your 2 starters that is basically built to be sacrificed with 9 traits, especially ancient power, which is required to not level up too fast in order to get the most potential from future sacrifices.
Well, I can suspect a nerf to such strategy, since it even surpasses god form if done right, and while you have less flexibility when it comes to fusing/breeding characters, the massive stats the main character has alongside good ability kit makes up for it. I don't know if a normal guardian is going to be affected as well, but that is truly the most busted thing that I'd say makes the best of gene distribution out of any character, the other 2 guardians have a severe downside that pretty much forces you to rush things in order to stand a chance, while the succubus can just eat some characters and get their growth if not more, while not having to suffer severe handicaps. I'd say its hands down the best neutral character overall, because with all essences and powers that improve characters growth, you effectively can become stronger and stronger to infinity with ascended and all the growth essences possible, and while you cannot have 2 guardians in the party due to elite status also applying to non-elite characters of same type, it means you can stuff your party with supports and other combatants to help yourself out.
Yes, it requires highest possible points for starters and main character, but since neutrals kind of...suck without genes/hidden power expect those that have engineered trait, it is also the character that negates the weakness of succubus guardian on top, since that character gets guardian upgrade at a point where said character already leveled up, reducing their effective power, but when you play as said character and get to pick traits before they level up, that makes them much better as main character than a unit that gets its niche fulfilled by a regular guardian with needed skills and traits, and that's on top you get all passives that are otherwise locked to individual choices. So you have a passive 10% chance for any unit of yours to avoid damage, getting 1 action point when casting 15+ mana spells like lightning storm, and so on.