Fighter Guild

That Sauronan is home to the Fighter's Guild may seem a bit strange, but with some thought it does make sense- Merchants and Abjurers need guards outside the city's walls, and Sentinels may need a bit more muscle for an arrest, that they need to pay only for that arrest.
The Fighter's Guild keeps its portal to the Adventurer's Guild in its Training Room. As with all portals between Guildhalls and Adventurer's Guilds, anyone can use the on to the Guildhall, but will need to walk back to the Adventurer's Guild unless they are members of the Guild.