H! Jakob Help!!!!!!!!!!3!::!:!:!!:$3&2$$2$2$!2!2$$

I'm struggling with this too...sort of. I'm debating on giving my F!Robin Close Counter. I only have one Takumi, so...yeah. But that's enough about me.

Here's your build:

Weapon: Monstrous Bow/Brave Bow+ (Doesn't need to be +Atk to use it)
Support Skill: Pivot/Swap
Special: Bonfire
Passives: Distant Defense 3, Wary Fighter 3, Atk Ploy/Panic Ploy
Sacred Seal: Atk Smoke/Breath of Life/ Quickened Pulse/ Attack +3/Distant Defense 3 seal

Yes, both the Distant Defense skill and seal stack so it's +12 making Jakob a literal wall, both physical and magical defense wise.

Since your Jakob isn't +Atk, a good set could be to bait mages/archers especially with his bulk.

Something like:
Slaying Bow+
Swap/Pivot/Reposition(if using Armor March)
Bonfire/Moonbow(instant damage)
Distant Def 3/Atk Res Bond 3/CC (whenever you get a Takumi)
Wary Fighter
Whatever you need
Distant Defense Seal/Quickened Pulse

Hope this helps.