First and foremost it scales brilliantly with any graveyard effect cards
This red, white, and black legendary Angel lets you take an Angel, Demon, or Dragon card from your hand and play it tapped and attacking when you have Kaalia attack an opponent
This highlights the importance of including some decent green card draw in your decks
The upsides of doubling your draws and life gain in the late game can really push this over the top of a usual mana rock

Abigale, Poet Laureate Agent of the Fates Akroan Conscriptor Akroan Crusader Akroan Line Breaker Akroan Skyguard Anax and Cymede Anax and Cymede & Kynaios and Tiro (playtest) Anthousa, Setessan Hero Arena Athlete Artisan of Forms Ashiok's Adept Battlefield Thaumaturge Battlewise Hoplite Bloodcrazed Hoplite Brigone, Soldier of Meletis Centaur Battlemaster Chorus of the Tides Cleon, Merry Champion Dawnbringer Charioteers Elite Skirmisher Fabled Hero Favored Hoplite Hero of Iroas Hero of Leina Tower Labyrinth Champion Lagonna-Band Trailblazer Leonin Iconoclast Meletis Astronomer Mindreaver Phalanx Leader Pheres-Band Thunderhoof Rosnakht, Heir of Rohgahh Sage of Hours Satyr Hoplite Setessan Battle Priest Setessan Oathsworn Staunch-Hearted Warrior Tethmos High Priest Tormented Hero Triton Cavalry Triton Fortune Hunter Vanguard of Brimaz War-Wing Siren Wavecrash Triton Weird Angel Flame Wingsteed Rider