Boros Aggro pressures hard with Momo, Friendly Flier and dragons like Magmatic Hellkite and Nova Hellkite, so Sheltered by Ghosts both exiles one of their early threats and gives one of our creatures lifelink plus ward 2 to stabilize against their burn and combat damage. Esper Origins and one Shared Roots are cut since they're too slow to matter in this aggressive race. We keep every piece of our landfall core since outracing them with bigger bodies is still our best plan.