Don't know if he's my favorite (dpends on the enemy of course), but at the moment I'm using a fun build with Konstanten as a Barbarian/Skald with WIllbreaker/Body Blows, Spirit Frenzy, Thunder Rolled uügrade, Ben Fidel's upgrade, Bard Shouts and the Weakening chant.
Fortitude drops so low... until now I haven't met a foe whose fortitude was higher than deflection after everything hit him. Brute Force pays of every time. I don't even know iof the -2 MIG from the Weakening Chant stacks with the -5 MIG from Stunned...
It's -45 Fortitude (-25 from Body Blows, -10 from Stunned, -10 from Weakened (-4 from Weakening chant maybe?))
and -15 Deflection (-10 from Ben Fidel's upgrade, -5 from Shaken).
At the same time he interrupts on crit (ability) and 25% on hit (Willbreaker). And occasional Ed Nary (targets Fortitude!) rounds the picture.
I am interested in this as I have always gravitated towards "debuffing" type builds. I know you are using a companion in your playthrough, but if using the MC what attributes would be considered priority? Is is worth it to place many points in might due to you having the morning star modal on most of the time and suffering -25% damage? In my opinion Int/Dex/Per should be priority or do you debuff fortitude so much that Per does not matter?