Mummy is a strange animal. It has very different starting conceits than most Chronicles of Darkness games. First, when your mummy awakens, it is full of power but very little idea of who they are and why they are awake. They regain more Memory as they remain awake, but they also lose power at the same time. It gives an interesting pressure to each descent where you're racing against the clock of your own power. Also, the more Memory you gain, the more likely you are to develop your own desires and maybe want to rebel against your Judge (the dread power you serve.) However, if you do not do what your Judge wants, they can punish you by taking away some of your Sekhem and/or your Memory. So you can't just flip your Judge a bandaged-wrapped middle digit. You need to figure out a way to bend the rules without breaking them to accomplish any goals other than what your Judge had decreed.

Second, mummies do not experience time in a linear fashion as humans do. They, instead, can wake up (or Descend in game terminology) out of order. Their first Descent might be in 2021, but then their second could be in 1776, then 1942, then 420, then 3442 on Mars. It is an elegant way to get around the whole, "this may be my first time playing this Mummy, but they had to have awoken at some point prior to this, why are they statted as a beginning-level MummY?" question. It also allows you to tell very different stories than are normally possible. You can have a Mummy wake up to find out a Relic has been stolen from a nearby museum. They do their investigation and figure out how the thief broke in and stole it. However, they can't figure out WHERE the thief is. They seem to have just disappeared with the Relic. The Mummy then goes back to sleep and wakes up a few weeks earlier, and using the information they learned on how the thief broke into the museum, they steal the Relic for themselves before the thief can. That's not the kind of story you can tell in most RPGs.