This is done by MTG designers to show that the color is corporatist and selfish, and black is one of the colors where these definitions best apply
Three lands, some mana rocks that tap for colorless and an equipment arent going to do you any good without a body to attach the equipment to or a blocker to ensure Dihada survives for more than one turn cycle
As everyone knows, in the decks that made best use of the five Moxen blue was always the most sought after color due to cards like Time Walk and Ancestral Recall, so the Sapphire wins easily
Duelists Heritage, in addition to making your own attacks more potent, provides a pathway for political leverage on opposing turns with any creature which really wants to hit players
After damage, the Karn will still be on the board with 4 loyalty
(You can play a land this way only if you have an available land play remaining.) You may look at the top card of your library any time