Underlords vs. Underlord+
The Sword Sage and Li Markuth are both roughly two stages above Underlord.
The three entities listed by Suriel as the top of the Cradle food chain are FIVE stages above Underlord, including one big leap (like the difference between Truegold and Underlord, it's only one stage, but it's a big one). The Dreadgods are a threat on THEIR level--and notice that Suriel said the 8-Man Empire, Sha Miara, and Northstrider could save Sacred Valley from them. She didn't say they could destroy the Dreadgods.
The BF Emperor is the one person in the Empire who is a level over Underlord.
The EE Emperor is about his level, although since they're using different magic systems, it's less about stages and more about what they can and can't do to counter one another.