Mrachni was raised (if such it can be called) by a vile tribe of orcs, being taught war and violence from infancy. He never knew his mother or father, having been abandoned in the forest at birth and found by the tribe, who were suffering from lack of numbers at the time.
Mrachni never felt that he belonged with the orcs; they fed and clothed him, but still he bore the brunt of much ill-restrained hostility and age-old hatred. He managed to survive, day to day, but each day became more of a strain as tensions grew.
When he turned 14, the age of manhood for orcs, he was sent by the tribal leader to prove himself -- by ransacking a nearby village and bringing back a human female to ill-use.
Living in the wilderness, scorned by humans and by his own mind, and not daring to consort with orcs, he wandered from place to place, barely surviving at times. The actions his tribe had taken toward human villages during his youth filled him with a fear, a dread he did not understand. Even when he was nearly starving after fleeing the tribe, he could not enter a human village to steal from its inhabitants. Instead, he raided goblin encampments while they slept, stealing enough to survive another few days.
One day, after three years in the wilderness, Mrachni awoke to find himself bound and being dragged across the forest floor. The mob of humans who'd somehow stumbled across his hiding place considered him an orc -- and how could he blame them? They dragged him into their marketplace and tied him to the central pole, before beating him senseless.
For two days they continued this treatment, neither feeding him nor providing water for his thirst. He could not understand their speech, and his attempts to communicate in Orc were extremely short-lived. On the third night of Mrachni's captivity, a strange human approached him, glancing around warily as if afraid of being seen. The human spoke, but the voice was neither angry nor resentful. Mrachni looked up, and there was kindness in the face he saw. The paladin cut his bonds, healed his wounds, and beckoned for him to follow. He followed.
Over the next four years, Mrachni learned of Iomedae, goddess of righteous valor, justice, and honor. As he learned, the knowledge grew within him that he must repay the debt he owed the goddess -- the debt for his life, which her servant had saved on that cold winter night. Recognizing his debt, he pledged himself to her service, carving her symbol into his flesh in the ignorant way of his people... and she astonished many by responding to his pledge with her clear favor, given in the form of abilities, knowledge, and mercy no half-orc outcast can expect.