Lie-in Heart is a white lion with yellow eyebrows and inner-ears. His nose and eyes are orange. He has a milk-blue mane with ice blue tips. His many tail flames and chest fur match. He wears a yellow vest with burnt-orange sash around the middle, a pair of dark teal pants and wristbands, and dark yellow toed-sandals. He carries a long nihonto-like sword with a maroon sword sheath on the left of his waist.

Lie-in Heart has a very patient soul, to the point of appearing unwilling to act. He waits for the perfect moment to act, but tends to wait days on end for that to happen. He will make you wait for the perfect moment to do anything, along with a perfect setup. Once the time is ready, Lie-in Heart will make everyone perform whatever they were waiting for to do with a spectacular performance. This is rather risky; it can cause the victim to continue procrastinating to the point where time has run out and the "perfect moment" will never come.