It's sort of like a stronger Tooth and Nail
The 2-mana artifacts are at their absolute best in mono-colored decks, where their cost reduction applies to nearly all cards in the deck
Pillar of War takes some ideas from golem folk tales, including how theyre meant to protect a particular place and lie dormant until that places hour of need, and transposes it to Theros Grecian setting
For example, Umori here mandates that all nonland cards in your deck share a card type, but once its on the battlefield, it makes it easier for you to cast those spells
And then you get to start making 4/4 Dragon Elementals with flying and prowess every time you manage to get two cards cast on a single turn
Shay removes any and all of these annoying keywords for the low cost of one generic mana while also growing into a sizeable threat himself in a deck with a handful of targeted removal