One dragon, two dragon, red dragon, blue dragon; aka why the Twinbird that the Deathbirds serve is really a Twindragon.
This is the Twinbird Kite Shield. Its description says: “Shield featuring a vividly painted twinbird. The twinbird is said to be the envoy of an outer god, and mother of the Deathbirds. At dwindling levels of HP, this shield slightly boosts both attack and defense.”
The shield & its description give us a few clues to figure out the identity of the twinbird:
Draw your attention to the colors of the Twinbird. The “bird” on the right has red wings and is on a blue background. The “bird” on the left is on a red background, but is colored black. Why make it black on red? It would have been easy to make the Twinbird’s colors exact twins: red on blue, then blue on red, but instead they made the left one black on red. It’s extra weird because two talismans associated with the Deathbirds have blue & red feathers: the Blue Branchsword Talisman & Red Branchsword Talismans.
Deathbird association + blue & red colors + feathers == fits with the Twinbird shield. The black-that-should-be-blue color of the left twinbird is an anomaly. But, and I swear this must be intentional, there’s another pair of red + blue items that feature a black-that-should-be-blue. The Red Crest Heater Shield and the Blue Crest Heater Shield.
Blue Crest Heater Shield: A medium-sized metal shield. Easier to handle than a kite shield. The crest represents a forest and river.
Red Crest Heater Shield: A medium-sized metal shield. Easier to handle than a kite shield. The crest symbolizes red wings.
The Blue Crest Heater Shield is described as blue and is said to depict a river (which are usually colored blue), yet it is very clearly painted black. The Blue Crest has a black-that-should-be-blue. The Red Crest Heater Shield has a red crest that symbolizes red wings. The qualities of these shields together are 1) red & blue pairing 2) black-that-should-be-blue 3) red wings. The same qualities we find in the Twinbird Shield and the Branchsword talismans. These shields are part of this puzzle.
I looked through the rest of the shields for more clues and found two more which featured red wings. The creatures with those red wings are dragons.
The left shield is the Dragon Towershield, which features a red dragon with red wings. I even wonder if the crest below it is meant to look kinda like the Red Crest Heater Shield to help our brains make the link. The right shield is the Kite Shield, which features a red dragon with a sword stabbing downwards. Its red color is very, very faded, but it’s definitely red. Three makes a pattern, and we have three shields depicting red wings, two of those three depicting dragons. I think what we are meant to conclude is that the red wings in this puzzle are red dragon wings. The red wings linked to the Red Crest Heater Shield, the Red-Feathered Branchsword, and the red Twinbird are dragon wings because the red Twinbird itself is a dragon.
Whoa wait up the Twinbird Shield and Red-Feathered Branchsword clearly depict feathers dragons don’t have feathers, do they? Actually turns out they do, they literally all do. Here is a shot of Greyoll, you can clearly see the feathers in her wing.
It must be inspired by how birds are the descendants of dinosaurs.