Mary Todd[]
During his time as Abraham Lincoln, Immortal married Mary Todd. It is unknown whether she was aware of The Immortal's powers, including his immortality.
Katherine "Kate" Cha/Dupli-Kate[]
Kate is a member of the Guardians who can make copies of herself. The two had few interactions when they first met, but end up taking a shower together after a training session. They became intimate and are interrupted by Rex who calls him out on his hypocrisy. Kate points out that they were never an item while she and the Immortal are. They both shared a common denominator; they both know the feeling of dying many times. He was greatly depressed by her death, but was overcome with joy after learning that she survived.
Mark Grayson/Invincible[]
The two had a rocky start, as Immortal thought Invincible would become like his father, who previously murdered the original Guardians, including Immortal. However, over time, Immortal began to respect Mark and see him as a true hero, eventually considering him one of his friends. When immortal fought the Noggolesible (Lenseless Invincible) during the Invincible War, he called the variant a pale imitation of Invincible, showing his respect and admiration for the mainstream one.