Ripping from Android games?

I would like to rip models from an android game, but i don't know how, so, does anyone knows how to ripping 3D models from an Android game?
I want the models from an specific game, is called Summoners War: Sky Arena.

This is the model: https://lh6.ggpht.com/67RLPZqBSB6_K5rsr2...u2Tug=h900
This is the game: https://play.google.com/store/apps/detai...&hl=es_419

Thank you from now on for your answers, and sorry if my english is no that good.