This video – Spine2D Unity Setup: Søren Juul Øllgaard – shows you how to implement Spine2D characters into Unity.
Spine2D is a 2d animation studio made by Esoteric Software.
For the most part, we animate everything inside of Spine, add events to specific keyframes (see this video about Spine-Unity Events) and then import the Spine Character Model into Unity.
You can essentially control the character’s animations from within any C# Script provided that you insert the correct libraries. You do need to download the Unity Run time library (it can be downloaded here).
There are more tutorials out there on this topic, but the best bet is to look on YouTube.