"The God of Fire at Red Cliffs 赤壁的火神 (chì bì dè huǒ shén)"
Why is he a Demi-God:
People familiar with the Romance of the Three Kingdoms story would know that Zhu Ge Liang 诸葛亮 and Zhou Yu were both instrumental in defeating Cao Cao 曹操 at the Red Cliffs. However the historians that distilled out the "Romance" from the story found that Zhou Yu was the main architect of the victory, while Zhu Ge Liang had far less involvement. Even then, we can already tell in the story that Zhou Yu did a lot of the dirty work in putting the pieces together. These include:
1. Setting up Pang Tong 庞统 to deceive Cao Cao into shackling his ships together.
2. Sending Huang Gai 黄盖 to feint defection in order to set start the fire.
3. Planning for the cut off of Cao Cao's retreat.
Ultimately, Zhou Yu deserves the credit for destroying Cao Cao's entire army and that is why Zhou Yu deserves to be immortalized as a Demi-God!
Character ability 1: "The Sound of Music 琴音 (qín yīn)"
During your discard phase, when you discard 2 or more on-hand cards, you can choose to force all players (including yourself) to regain 1 unit of health or lose 1 unit of health.
Character ability 2: [Single-Use ability] "Searing Heat 业炎 (yè yán)"
During your action phase, you can select 1 to 3 players and distribute a total of 3 units of fire attribute damage between them. If you allocate 2 units or more of damage to any of the players, you need to discard 1 card of each suit (4 cards in total) and lose 3 units of health.
Ability's relation to story:
Although Zhou Yu is known for his superb skills with the Qin instrument, there does not seem to be any mention of him playing the Qin during the Red Cliffs episode. Thus I believe "The Sound of Music" is just loosely based on his ability to play. "Searing Heat" probably just refers to his fiery achievement in defeating Cao Cao, but there is no reference for his sacrificing his health in the story at this period of time. Therefore this is probably also loosely-based on the story.