But my question is: ¿Is possible to create a ride pose action and use it without break the monster graphics?. I did a different pose of the Evol online for this example

And after test this idea, it didn't work because the player graphics layer are placed always over the monster graphics layer, so the monster graphics got broken in south view when the monster head is overwritted, or when player arms/legs are around the monster head/ears on side views.

¿The solution?, ¿the long-waited paper doll system? Maybe it can solves all the graphics layer problems, but by the moment I just edited manually the monster spritesheets, and for testing I used the item transformation feature to transform me into monster+human spritesheet and "ride".

It didn't solve other problems as show the items that player got equiped while riding on the mob, the hairstyles and races... but can be an excuse to use a wearable item required to ride for example. like a cape or full dress robe
For example: a robe that only let show the player face replacing other items, like the teleporter's robe:

the robe is dyeable, so we can use different colors for different monsters and features... Just dropping the idea.