I have Minthara as basically a Paladin of Shar in my current run. The entire party bows to Shar after what went down in Act II, and Minthara's was pretty much "By My Oath" nodding in agreement. She looks badass in the Dark Justiciar armor, and there's definitely enough Shar themed gear to go around for 4 party members to dress the part hehe.
Of course the main Dilemma is who take slot in the 4th spot while you handle the stuff in the first Act.
I went with Necromancy Gale for that lol. Somehow he got himself killed almost immediately in my Evil Tav run, so it seemed thematic.
I did a Durge run much the same, but that one is a little different. It's been kinda buggy with the Minthara romance still in Act III, I still haven't finished that playthrough. You might go with Shadowheart for that, or just fly solo like dedicated only to Shar. Or just make sure to keep saving and clicking on Minthara to make sure she don't get the "You are bold to seek me out" romance loop. Otherwise she's good to go though and hits way heavy in the second Act.
