Soulkeep is part of the entire ecosystem of the Splinterlands game even the Land expansion - where you can purchase pieces of land called plots that give you the possibility to produce various things. Currently research points, grain and SPS token. I strongly recommend that you try to carefully read all the information present at the link next to it https://support.splinterlands.com/hc/en-us And that's just to discover what the game has to offer