The heart of this deck is the infinite combo of Felidar Guardian and Saheeli Rai, but this deck is so much more than that. Three other themes run through this deck: life gain, creature toolbox, and flickering. Normally spreading the focus of a deck would only hinder it, but in this case it doesn't, as the cards crossover between multiple themes.
Sometimes gaining enough life is enough to win a game of magic, and while this deck has no infinite life gain, it sure has a lot of incidental life gain attached to powerful cards. These cards include: Charming Prince, Knight of Autumn, Huntmaster of the Fells
, and Thragtusk. This incidental life gain helps against burn, out tempos faster creature decks, and makes life very difficult for Storm and Valakut strategies.
Oath of Nissa not only digs for your combo, but fixes your mana too. The deck requires four colours, so finding the right colour when you need the is important. However the deck only has a light splash of blue for Saheeli Rai and Deputy of Detention. Oath of Nissa helps with find your mana and also digs you deeper into your deck when you're looking for a specific creature.
Once you start looking at the creatures, your realise the sheer number of enter the battlefield effects. These all pair very well with the two parts of your combo, Saheeli Rai and Felidar Gaurdian. Copying or flickering Thragtusk is always a strong play, but even the smaller creatures like Charming Prince and Knight of Autumn benefit greatly from these interactions.
Cat Life is a very enjoyable mid range creature deck with a threat of combo. It's very interactive, and has some very great match ups against a lot of the modern field.
