Kenrith, the Returned King

politics + pillow fort is the name of the game ;-)

The idea of this build is to be very political to start. Form alliances, appear like you aren't a threat, make friends by helping them to wipe out your threats by using Kenrith's abilities to give their creatures haste & trample. Keeping your allies alive with his heal. Giving creatures +1/+1 counters to help their creatures live. Deciding who attacks who with Pramikon, Sky Rampart, using Mana Flare to pretend like you're just giving mana to help them, Etc. While you are playing the politics game you slowly build up your Pillow Fort, get a solid mana base and get your ability reducers on the field to pop off. 

Pillow Fort -- by the time you are set up they realize it's too expensive to attack you ;-)

Put stuff in the grave to cheat it out later w/ Kenrith

There are some higher CMC creatures that you can sacrifice via different mechanics and just use Kenrith's last ability to bring them back to the field. Bringing back Resolute Archangel over and over again from your graveyard keeps your health high. Sacrifice Dauntless Escort to give your creatures indestructible... then use Kenrith to bring him right back to sac again next time they try to wipe you. Use things like Buried Alive to get creatures into your graveyard to cheat them out with Kenrith's ability. Cards like...

Show them who's KING!

Now that you are set up you can use things like Defiant Bloodlord and Vizkopa Guildmage to make your healing into life drain. I like using Helm of the Host or Stolen Identity to copy them to multiply the effect. Use Kenrith 'heal 5' and turn that into a 20+ life drain for 1 white (with ability cost reduction). Use Axis of Mortality to swap some life totals around to make it easier and prioritize your targets. 

Cast Willbreaker then for 1 green you can put those same +1/+1 counters you used to help them to steal their big scary things from them and start swinging. Or just Mob Rule and turn all of their stuff against them with one spell. 

The most fun win condition for any King... 

You have been healing and getting things in place its time to live Happily Ever After. 5 colors among permanents is an easy condition. The 6 permanent types you have are 'Land', 'Artifact', 'Creature', 'Instant', 'Sorcery', and 'Enchantment'. With the quantity of each, you can easily get them onto the field or into your graveyard. Then just keep it alive until your upkeep and then... GG!!

...BACKUP PLAN...

If everything else fails... just turn everything into 3/3 Elks