Ye Rin is a half-breed with both Human and Another parentage. She joined Hon at a very young age along with Un Ga. She is as strong as a highly dangerous Another but the knowledge of this is not widespread.
After the kidnapping of Detective Park by Anothers, She alongside Yu-Hwa and Un are sent to rescue him. She displays a glimpse of her powers when she easily overpowers many battle type Anothers (Salamanders). She stops Jacra's attack on Yu-Hwa and later learns he is a highly-dangerous type another after reaching Hon.
When Yu-Hwa gets injured, getting involved with Ji-Woon and ends up in the hospital again, Ye-Rin answers Ji-Woon's call and reaches the hospital. She and Un admit him there and decide amongst themselves to not let their superiors know Yu-Hwa's involvement. However, Yu-Hwa leaves hospital to catch up with Ji-Woon without notifying either Ye-Rin or Un. The two agents catch up with him and consent on his coming with them to secure Ji-Woon and the Stone of Healing from anothers. Ye-Rin helps trace the location of the child with her tracking ability. Once they reach the spot, Ye-Rin and Un take care of the Another goons while Yu-Hwa accompanies Ji-Woon on his way to his dying grandpa. Later they visit the hospital and recollect the stone after Yu-Hwa uses its powers to heal Ji-woon's grandpa enough to enable him to convey his last words to Ji-Woon.
Ye-Rin attends a blind date with Yu-Hwa due to the repeated requests from Su-Jin. She visits him in the cafe. However, Ye-Rin has to leave embarrassed because of Yu-Hwa's unawareness of it being a date. She doesn't come into any further meetings with Yu-Hwa for some time. After Yu-Hwa has absorbed Lecter's Orb of Power, he comes to Hon for test training to see if his power has increased in anyway. Due to Un's injury, Ye-Rin becomes Yu-Hwa's sparring partner. She is hesitant to fight Yu-Hwa seriously as even her smallest attacks are too much for him to handle. The training results in spotting no significant difference in Yu-Hwa's power.
Later, Ye-Rin accompanies Yu-Hwa back to his cafe. Suddenly they are under enemy attack. They get rid of the Anothers pretty quickly and then set off towards Hon. Meanwhile, the Atran troops have launched an attack on Hon to procure the key to Pandora's Box: Su-Jin Ji. Ye-Rin arrives just on time to save Su-Jin and Yu-Hwa from Guight's attack. Asking Yu-Hwa to escort Su-Jin to the underground bunker, Ye-Rin remains to fight the highly-dangerous Another, Guight. The fight begins. Although Guight underestimates her at first, he realizes his mistake as the fight goes on and even considers her as a highly-dangerous Another. Ye-Rin is unable to finish him off because Guight flees away after being informed of Mase's approach. She then accompanies Mase to the bunker where they find Su-Jin and Yu-Hwa peacefully asleep.
Half Physiology: Ye-Rin is shown to be quite powerful even for a Half. She easily defeats battle types Salamanders. Like Un, she had also undergone severe training when she had joined Hon. It is revealed by both her partner Un and an Another named Guight, that her strength and skill are quite high, rivaled and possibly bested only by her fellow team mate and captain, Mase. Anothers wonder why she is not listed as a highly dangerous Another. Ye-Rin, however, claims that the reason is because she doesn't like to be noticed.
Physical Enhancement: She has enhanced strength and speed. She is able to channel her powers in her fists and feet and prefers hand-to-hand combat.
Energy Perception: She can see the traces someone leaves behind.  Something visible like footprints require normal ability but she is able to trace energy.