Something I need to say abt SR tanks.
Vargas
He is the current best SR tank. His tankiness rivals even ledin. Another good thing about him is he is very easy to increase stars because his bond gate is released at launch. If you are building an empire team, he is the go-to tank for the team.
Freya
She is great early, but falls later. She is the only tank for princess team, but high lvl princess teams go for ledin (if they have) cos' freya has a big issue. Her gate is not released at launch until very late in the game and she is very hard to increase stars, unless u are a whale or super lucky to pull a lot of copies of her.
In tw, her gate was only released recently and I have a hard time having her as a main tank because she is only 2*. 2 horsemen can kill her even though I got her 4* SSR armors.
Grenier is tankier than her (though his dmg sucks.)