St. Celestine has both increased in points (now 40 MBs) and abilities. Specifically, she gained 2W, so 5W total, Eternal Warrior, Armourbane for her sword, and two “free” Gemini bodyguards (Geminae Superia are WS5, BS4, S3, T3, I4, 2W, 2A, Ld10, 3+/4++) which can tank wounds for her and be resurrected throughout the game, as long as she is alive).
She also gained a new rule called Saintly Blessings: Celestine can give a 12″ radius buff to friendly non-vehicle Army of the Imperium units at the start of each of your turns. Each buff can only be used once per game, and affect units based on their Battlefield Role (ICs get affected as long as they are a part of the “targeted” unit for each type of blessing):
-HQs: Zealot until the start of the next turn.
-Troops: FNP 6+ until the start of next turn. If models already have FNP, they get a +1 bonus to FNP instead.
-Elites: Counter-Attack and Furious Charge until start of next turn.
-Fast Attack: Crusader and Fleet until start of next turn
-Heavy Support: Relentless until start of next turn
-Lord of War: It Will Not Die for the rest of the game.
Finally, as mentioned in previous articles, she can be taken as an HQ for any Imperium army in a CAD/Allied detachment and unlocks a set of 6 Relics for friendly Imperium characters to use. Considering all this, I think one of the most competitive ways to use Celestine, and particularly her Saintly Blessings, is in a CAD from an Iron Hands army… here are some ways I can see Celestine synergizing well with an Iron Hands force:
 Buffing Iron Hands Troops — Since His get FNP(6+) naturally, being able to buff that up to FNP(5+) for a turn can make a significant difference in a game, especially when you are moving Bikers into position for an important shooting phase or your Tacticals and Scouts are trying to hang on to an Objective for one more turn to gain required VPs. If IH Troops have Endurance cast on them, then with Celestine’s help they can be buffed all the way up to FNP(2+), making them VERY difficult to bring down for that turn (remember, any IC attached to them benefits from this as well).
 Buffing Iron Hands Drop Pod/Mechanized Devastators — With the ability to hand out Relentless for a turn, Celestine can take normally static Devastator squads and make them both more mobile and extend their weapon’s ranges. For example, if you Drop Pod a bunch of IH Devastator squads into enemy lines with MMs and/or Grav weapons and give them Relentless, they can fire to full effect that turn, delivering very potent firepower when you need it. Alternately, if the Iron Hands are riding in Rhinos, then can move up and still fire their Heavy Weapons through the Firing Points on Turn 1 with the help of Celestine’s blessings.
 Buffing IH Shadowstrike Kill Team — If you are using the Shadowstrike Kill Team formation, then you can get Celestine into position and bring the Vanguard Vets down via DS on Turn 2, with Celestine “casting” Furious Charge on them to make them more effective when they do charge. A great way to do this is to attach Celestine and her bodyguards to an IH Biker Command Squad (with an Apothecary) and attached Biker Chapter Master… between the Chapter Master and Celestine, plus enhanced FNP, the entire squad can easily weather a lot of enemy firepower, then turn 2, you bring in the Vanguard Vets and have them assault with Furious Charge. Additionally, the Command Squad makes Celestine and her bodyguards more survivability (i.e. majority T5 and FNP from the Apothecary) while she makes the Space Marines Fearless and gives them Hit and Run, so both units mutually benefit.
 Unlocking Relics — While IHs already have access to the Gorgon’s Chain and the Shield Eternal, Celestine allows them to also access the Shroud of the Anti-Martyr , which means you can potentially have up the three separate characters with Eternal Warrior (well, four, counting Celestine herself) in your army, making it very difficult for you opponent to deal with them (don’t forget, IH characters also get FNP(6+) and IWND naturally). Alternately, you can give one of your Iron Hands ICs the Blade of the Worthy and another IC the Burning Blade, allowing you to have two different characters that strike at S6+ AP2 at full initiative.