"I know, his offense is * great (high damage + ignition)"

Ok great glad you know this.

" But I think he can be easily killed. No immunity, no super armour, no ability to evade skills, no self healing, no defensive scalingbuff plus no revival. But one defensive skill is creating spider bombs. Cause they can take standard attacks' damage"

What? You already established what you know he is meant to do so why would he be defensive?

" But He can be targeted and debuffed as well."

You mean just like a lot of other ninjas?

"Even he's used with other metas like agk, egk or kisameshark, he can be targeted and easily killed because of his very low defensive side. Is there a solution for this?"

He is a character just meant to do damage, nothing more. Everything has a counter, your best bet is to run him with Jigokudo/Jinpachi or Jigokudo/Sailor Sakura if you're so worried about him being CC'd.