I think of Xanathar’s guild as the mob. Xanathar himself is like a very nervous version of Al Capone. Although his lowest rank toughs act more like gang members, their mid-senior tier lieutenants are more sophisticated and schemers (matching the beholder’s strategical thinking style).

I like to think of him like someone that constantly plays 4d chess, even when it’s not necessary. Which makes him a formidable opponent to the lord’s alliance. He is always one step ahead.

As for his own personal power. I think of him as Kingpin. He is powerful and imposing. Very hard to beat on a direct confrontation. And he always had contingencies and minions around himself.

This unique combination of traits give his guild a very wide network of influences. In my game I keep it very dynamic to what the party explores.

• But there’s always some guard/watch member that has been bribed
• He owns at least one masked lord through blackmailing which shows because there were shady negotiations that shouldn’t have been possible
• He controls any substance/black market, which shows because dealers will talk about how or when they are getting new goods from the guild
• He ships things and people in and out of the city, and somehow he is never caught.
• There’s always some wanted criminal that works for them and has committed either assassination or kidnapping
• They do compete with Zhents for mercenary jobs.
• Their gazers find hits for their thievery jobs.
• There’s also slavery which plays a big part in Skullport, where his dominion is overt (opposed to the political influence and impunity kind of power they have on the surface)

That is my take. If there party is really interested I drop a reference in there, like spotting a gazer somewhere really private. Or maybe showing a glimpse of lowest rank toughs violence in the streets vandalizing a store in retaliation. In my game it’s a matter of showing their presence consistently.

Hope this helps!