This is my first competitive modern deck. I love the lifegain as well as prison effects. I'm constantly trying to tweak it based on my meta. Currently, there are the typical decks like Jund, Mardu Pryromancer, Collected Company and Humans. Starting to see more control, which is a terrible matchup.
Breakdown on card choice is below. Always welcome feedback on how to make it better.
Creatures:
Soul Warden/Soul's Attendant: This is the typical Soul Sisters package. Gets the lifegain engine going.
Ajani's Pridemate: Takes advantage of the lifegain triggers from the Soul Sisters. Becomes an immediate threat once the engine is going.
Auriok Champion: An additional "Sister" that is 2 cmc but has protection from black and red.
Ranger of Eos: Great tutor and card advantage. Can find the Soul Sisters and Ascendant. I've found that I need card draw, especially late game. Ranger keeps my lifegain engine going.
Archangel of Thune: Win condition; buffers all the 1/1 creatures and becomes hard to handle.
Ajani Goldmane: New to the deck; going to test. I'm excited that the life gain will trigger many of my win cons. Also, being able to buff up my little creatures is nice too. Not looking to ultimate necessarily.
Instant:
Path to Exile: Playing a full playset. Gets rid of creature threats the opponent controls.
Forsake the Worldly: Playing one just in case I run into an artifact or enchantment before I find my Oblivion Rings. Can cycle away for card draw.
Sorcery:
Spectral Procession: This card can win me games. It helps the lifegain engine when there's Soul Sisters in play. It will trigger Ajani and Archangel of Thune. It also provides flyers and chump blockers if need be.
Enchantment:
Ghostly Prison: This card has saved me many games. I like adding a touch of prison effects into this deck. When against playing creature-heavy decks (our best matchup) this card will slow the opponent down and also buy time for the Archangel.
Honor the Pure: I'm only so-so on this card. It's an enchantment that provides and anthem for all white creatures. It's good because it buffs up the 1/1 Soul Sisters and tokens and keeps them out of range from Izzet Staticaster, Goblin Chainwhirler and the like.
Mark of Asylum: This is a new enchantment to the deck to help with the control and burn matchups. This will protect creatures from any damage dealt outside of combat.
Oblivion Ring: This card helps take care of other enchantments, artifacts and planeswalkers that we otherwise have a hard time dealing with.
Lands
Plains: Base land for the deck.
Field of Ruin: Helps with the manlands and tron lands.
Kabira Crossroads: Comes in tapped, which isn't ideal. But the lifegain hits triggers.
Nykthos, Shrine to Nyx: New add to help with mana ramp. Going to test to see if I can get to Archangel faster.