We just got ambushed in a courtyard by about 15 enemies standing on a walkway above us, with no immediately obvious way for us to get up there. We were sitting ducks. So Shadowheart cast blade barrier across the entire walkway. In addition to doing a lot of damage every turn, it imposes difficult terrain. All of the enemies stopped firing on us and tried to run to the end of the walkway. Most of them died on the way, but a few seemed to realize it was futile and turned around to run back and attack us, they died on the way back. A single concentration spell turned a dire situation into a complete bloodbath for our enemies. Shadowheart doesn't shine very often, but when she does, she shines like a diamond.
If its the courtyard I'm thinking of, a well placed fireball can also be the most satisfying spell of the game.
My favourite spell for Shadowheart was always spirit guardians. Partly just because it was funny to watch her dashing around the map, mopping up weaklings.
Bless at low-to-mid levels and spirit guardians later are the best things Shadowheart can spend her concentration on for, like, 95% of situations. Both spells are extremely good, just like they are in the tabletop. Never understood people criticizing Shadowheart for being useless; she’s a Cleric, and that’s great already even if her subclass (which you can respec her out of) is subpar for the class.
She was so slow for most of the game that I couldn't make much use of those. Near the end she got some boots that gave her freedom of movement, and longstrider, and then I started doing the same thing with her. Just using dash and running over next to everyone. LOL
Edit: it was the courtyard right before you start climbing to get to the brain. I dropped an ice storm on top of the group with the spectator, and that was pretty satisfying. It killed everything except for the spectator. Is that the courtyard you're talking about? My favorite playing with fire moment was a fire bolt in the sewers on all of those grease monsters. Half the sewer went up in flames!
I make Gale an Evocation wizard every time, and spend almost all his spell slots on Shatter, Fireball, and Ice Storm. He mops the floor of a crowd very efficiently!
I always use her first bonus action after casting Spirit Guardians to cast Spirit Weapon. If nothing else, Spirit Weapon is great to distract enemies into attacking it rather than our party.
I like to use the spike growth/hunger of Hadar combo, really fucks them up cause they have slow from Hadar, difficult terrain from spikes, damage from both and blindness.
Yeah it's a really underutilized spell because you look at it and you look at entangle, and entangle hard stops them, and on instinct it seems better. Spike growth slows and damages so much though it's a great way to control a battlefield. At it's best during that fight where you protect halsins portal in the shadow cursed lands.
Cloudkill is how I deal with those fucks. Get to move it every turn so if they run out you just plop it back down on top of them. I use cloudkill to great effect in the throne room too.