I always used Herc in the JP version, so yeah I'm pretty surprised at how much of a tank he is at such a low level. I was gonna use the free 4* to pick Herc, but I don't think I'll bother now. Marie or Martha it is!Lu Bu does excessively excessive amounts of damage. He's a pretty absurd 3 star, and the only reason people don't rave about him more is because Herk is similar but more survivable.
Later on, he even gets an NP damage up for himself. Going off only self-buffs, Lu Bu some of the highest NP damages in the game- especially since he's free to NP5 compared to gold servants which are very difficult to get above NP1.
Edit: And just as I posted that, I rolled Vlad. Not a bad start to the day.