Rank up keepsakes?

[EvilShuckle]

Can't find something on the internet about it. There is the option to give these... nectar thingies to gods after the first but I've read they do nothing but add some additional dialogue at the moment. But also when you have these keepsakes, it says you have to do something to rank it up. What do you get for doing so? Is that implemented or does it do nothing?

[VK]

You can equip one keepsake per run (and actually change it after each boss battle). The first you choose it in the cupboard thingy in the area you select your starting weapon. It clearly states what each keepsake does and actually it levels up after clearing 25 rooms which each equipped.