Burich

Burich can be found in Dragomir's Tomb in Baldur's Gate II: Enhanced Edition.
To get to Burich you need to operate the tomb (use it) then crawl in. You may need to take two or more characters with you to defeat him but he gives you the Iron Rod you need to complete the stage. You need to take the rod back to the entrance room and use it in the wall where the light is highlighting.
By questioning his orders he can be convinced to give up the rod without a fight:
Regardless, he will turn hostile after the Shadow Fiends appear next to the dead-end tomb in response to their scripted Shout() actions.GENSHT01.BCS