Assassin’s Creed Origins: Curse of the Pharaohs – Pyromaniac Trophy / Achievement Guide
For this trophy, you need to “Kill a Mummy by setting it on fire”. This is easily done in the area:
There is a small dock below the fast travel point called DOck of the Eclipse. There is a mummy here, and he will not leave the wooden dock he is on. You can easily set this on fire to defeat the mummy and the trophy / achievement will unlock shortly afterwards.