The Judge is a transcended being that determines if a species is worthy of transcendence or if they should be annihilated, and then passes down their fate depending on the test subject's success or failure

Lexa was now a part of the test and she wasn’t prepared for memories of her dead girlfriend Clarke to be brought up.

Sometime later, long enough for Lexa to be annoyed by the Judge's absence, the Judge reappears as Clarke, knowing that Clarke was Lexa's greatest love.

The Judge however not only had access to Clarke’s form but her memories and personality as well, but to be fair the Judge had access to everyone’s memories including Clarke.

Lexa sighed, refraining from showing too much vulnerability despite her overwhelming urge to hold “Clarke” and breakdown in tears

Judge/Clarke responds I’m not her, Lexa.

Lexa brokenly says I know. The test can’t be stopped can it, Cadogan made sure of that.

Judge/Clarke responds No. I'm sorry. We can't stop what's been set in motion. Your species must now be judged through you.

Judge/Clarke walks over to the pool of blood leftover from Cadogan's body This man was unarmed, no threat to you, yet you killed him. Why?

Lexa justifies herself He killed my daughter.

Clarke dismissively asks Is Madi dead?

Lexa defensively replied No, but she will be because of him.

Clarke criticizes Thought Clarke taught you to be merciful

Lexa defensively replied I gave the world the mercy of not enduring a madman

Clarke speaks Lexa

Clarke says in Trigedasleng A rose by any other name is still...blood must have blood.

Lexa snapped You don’t know my pain!

Clarke counters You're wrong. During the test, I sense every part of you. I'm feeling your pain right now.

Lexa argues Really? Then feel me holding Clarke as she dies. Feel me seeing Costia’s mangled corpse severed from her head. Feel me lose everything to save my child, only to have her die anyway. Feel that!

Clarke judgmentally replies You suffer and inflict suffering on others. Pain begets pain. That's not mercy, Lexa. You say you do these things to protect your people, but you're all one...people. That much Cadogan had right. After all life is about more than just survival.

Lexa gets frustrated with the self righteous Judge especially since they are without consent using Clarke’s form, they were using Clarke’s words against her, Lexa hated that it wasn’t Clarke yet acted somewhat like Clarke, Lexa hated that she despite hating the Judge’s stance wanted the Judge to keep Clarke’s form just so she could be with Clarke in some form

Lexa finally replies He created a world without love to get to you. He killed my child to get to you. Have you ever considered that you're the problem? How dare you judge me when you annihilate entire species because they don't live up to your ideals? You say I should be merciful but you aren’t, you hypocrites! You think you’re better than me but the truth is you’re the worst version of me multipled on a galactic scale!

Clarke seemed detached and unaffected as she coldly replied I am sorry for all you have lost. You've borne so much...but if you are humanity, then I'm afraid humanity is not worthy of taking the next step. It has been decided.

Clarke twists the knife further as she speaks in Trigedasleng and quotes Lexa Your fight is over.