Being hot-blooded with

血(ち)の気(け)が多(おお)い describes someone hot-tempered and quick to fight. English equivalents include “hot-headed”, “quick-tempered”, and “having a short fuse”.

Literal Meaning

The phrase describes someone as having abundant 血(ち)の気(け), the vigor associated with blood.

Examples

A hot-blooded cavalry battle with 血の気が多い

Manga panel from キラキラとギラギラ showing example of A hot-blooded cavalry battle with 血の気が多い.
キラキラとギラギラ » Volume 4 » Page 85

During sports day, the events break for lunch. Lulu joins her friends, and they discuss the upcoming afternoon activities.

響子(きょうこ):
「騎馬戦(きばせん)は特(とく)に血(ち)の気(き)が多(おお)いけど」
“The cavalry battles are especially full of hot-blooded guys, though.”
清美(きよみ):
「うちは番長(ばんちょう)がいるから安泰(あんたい)だよね~」
“As long as the big boss is here, we're safe and sound, right~”