Should I level Ibaraki (Banana berserker)

IMO ibaraki is the 2nd best 4 star berserker in the game right now, right behind herc.

She fights on the front line better than herc because of her defense and healing and has much more utility for gimmick fights with self debuff removal and enemy buff removal. She also has better np generation than a typical beserker.

That said, she mostly excels at difficult boss fights so there are not a lot of occasions to get use out of her. IMO I would try to get her raised before next Nero fest but I wouldn't rush it.

Ibaraki needs a lot of investment and a team giving her defense buffs, she's not as braindead as Heracles and she requires a lot of investment for similar results.

So if you have limited resources and you don't like Ibaraki that much, i would reconsider it.

If you've maxed your Herc Bond level then Ibaraki could be your main ST Zerker. Frontline attacker like Ibaraki is a pretty solid Zerker if you want a strong one.

We all have limited resources in this game, gameplay wise Zerker with high atk and good survivability kit like Herc and Ibaraki is recommended. You can bring Zerker everywhere as long as you can cover or protect them.

Prioritize King Hassan first if he's your favorite servant, it's still up to you.

Bonus : i have a Bond 10 Herc, Ibaraki NP 2, Frans, Tamamo Cat NP 3. If you have lots of good zerker and you're confused on who to raise first, decide it by using their Bond level.
I have Bond 10 Herc, so Ibaraki NP 2 is my main ST Zerker now. She has Atk Up + Def down ( her NP ) + NP Up, so imagine you put a Buster CEs there. Different buffs stack multiplicatively while the same buff stacks additively.

Berserker like Ibaraki is a pretty independent and amazing unit and you have her sitting at NP 2, raise her if you already get your materials.