In Wanheda (Part 1), Niylah helps run a trading post with her father. Clarke waits for her father to leave before she arrives with a black panther she has recently killed in the woods to trade for supplies. Clarke and Niylah chat in Trigedasleng and Niylah offers her a drink. Clarke notices Niylah is wearing one of the Delinquents' wristbands. Clarke asks Niylah about how she got the wristband, but they are interrupted by Roan and another warrior looking for Clarke. Roan notices Clarke before asking if Niylah has seen the woman in a picture he is carrying around. Niylah tells Roan that Clarke was there two days ago and that is how she got the wristband but Clarke left to travel north, following "Eden's Path" into the Ice Nation. Roan and the other warrior leave to find Clarke. Clarke asks Niylah when did she figure out who she was and Niylah tells her since the beginning. Niylah switches to English and offers her a drink again while they wait for Roan and his companion to leave. Clarke asks why Niylah is helping her. Niylah reveals that her mother was taken by the Mountain Men and Clarke stopped the Reaping.

Niylah later helps Clarke clean the wounds she sustained while killing the panther. Niylah asks about the Mountain and Clarke says she did what she had to do. Niylah tells her she wiped out their greatest enemy by herself. Clarke kisses Niylah and they have sex.

Clarke later wakes up from a nightmare next to Niylah. She gets dressed and leaves the trading post, but is captured by Roan.

In Wanheda (Part 2), Niylah is seen being beaten and thrown around inside her trading post by Roan's partner. The Grounder wants to know where Wanheda, Clarke, is. However, Niylah refuses to give him any information. The Grounder pulls out a knife and says he will only ask once more, and then threatens to cut off her hand if she doesn't tell. Before she can answer, Bellamy, Kane, Monty, Hannah, Indra, and Pike enter the room. Bellamy shoots and kills the Grounder. Indra realizes that the Grounder was a bounty hunter. Indra then reassures Niylah that they are there to help and tells her that they are looking for Clarke, but she points out that he was, too, gesturing to the deceased bounty hunter. Niylah recognizes them as Skaikru, as Bellamy begs her to help them. Niylah ends up telling them that Clarke had been there last night, but that she was gone when she woke up. Kane asks Niylah if Clarke gave her any indication of where she was headed, and Niylah says she didn't but the bounty hunter did. Niylah then explains that the bounty hunter claimed that his partner from Ice Nation came back for her. She wishes them the best of luck before they leave.

In Nevermore, Clarke and the group need a wristband to fry A.L.I.E. from Raven's mind. So they go to Niylah and when she refuses to help them, Bellamy aims at her and violently tells her to let them in. Later, when possessed Raven reveals that Bellamy was the one who slaughtered her father, Niylah runs in and slaps Bellamy exposing their location to A.L.I.E.

After Raven is freed from A.L.I.E and the group is leaving, Clarke tells Niylah to stay safe from the AI and Octavia trades a lantern for a new outfit and Niylah nods.

In We Will Rise, she is seen after sleeping with Clarke. She insists that Clarke rest but Clarke says she needs to help bring the Hydrazine to Becca's Island for her mom and Raven. Niylah tells Clarke that Lexa would be proud of her and Clarke asks that she remain in Arkadia so she will be given nightblood once it's made.

In God Complex, she performs a grounder ceremony for those that died in the black rain.

In The Other Side, she is in the bunker sleeping quarters when Clarke walks in and they rest together.

In The Chosen, she is viewed as a traitor by Trikru because she was living with Skaikru, but the Sky People do not want her either and Geoff Hardy attempts to throw her outside when Octavia arrives stopping them and saves Niylah's life.

In a flashback in Red Queen, 46 days after Praimfaya, she comes to Thelonious Jaha in the bunks as he is finishing reading a story to Ethan Hardy, and asks him to help her fix the wheel on her cart. As Thelonious finishes Grounders barge in, Thelonious orders Niylah and Ethan to hide under a bed. The grounders.