You can get mini games token from winning the mini games event which start every hour. This token can be exchange with other item from token npc at Gungnae (110, 143), you can exchange silver tools for gathering here and exp gem to store your experience, once you store your exp into exp gem it will become shining experience gem, this shining gem is require for grade 3 and for reincarnation so you will need a lot of token to exchange in this npc

1 exp gem = 3 mini games token

Grade 3 require 10 shining exp gem = 30 mini games token
First reincarnation require another 10 shining exp gem
and more exp gem for 2nd, 3rd and etc reincarnation.