Merge or fodder?
I have a +Res -Hp Tibarn and he has just his base kit. But today I got a +Atk -Spd Tibarn. So I was thinking about merging them to erase the spd bane, but I really like some of his abilities :p
+Atk/-Spd Tibarn can actually work fine in most cases because he can double regardless of speed with his PRF strike. Between his own PRF and his native Sturdy Impact, he doesn't need speed to gain or to deny a double on player phase.
You want to wait for the March update before foddering Tibarn though, you can give Sturdy Impact and the entire 3-skill chain of either his B or C skill after the 4-Skill inheritance update.
I'm currently using a speed bane Tibarn and running it with galeforce and heavy blade. Works just fine coz of his sturdy impact guaranteeing follow up attacks when enemy at full hp. With galeforce he can get out of danger anyways. If not, i always have him with beast dancers to get him out of the enemy's range