The 10/27 build containing the point-based Upgrade system and new starter demons has been released! With many Upgrades now cheaper than before, there should be new and interesting possibilities available for upgrading your Relic.
Also worthy of the mention: the Titan's Fist Relic's starting Upgrades now provide a way to play with little or no summoning. Demons will still be necessary for success with such a build, but as teachers and Soul Armor / Consume sacrifices more than active participants in combat.
Cheers, and good luck in the Tower!