Not for grading

1) tu enténèbres, tu encres - you bring death and darkness
2) tu (t')affadis, tu (te) désépaissis - you pale, you fade (away)
3) tu (t')affadis, tu (te) ravives - you fade (away), you resparkle

I think this involves a lot of guesswork as to what the intended meaning might be, hence my confidence level and three interpretations.

Ideally one would be familiar with the characters and plot of The Gunslinger and the rest of the The Dark Tower series in which Roland Deschain, the last member of a knightly order known as gunslingers', has been chasing his adversary, "the man in black", for many years [Wikipedia] …

A little more context gives:
"The smell beneath the alkali was that of the devil-grass [described as 'opiate-like'] which brought sweet dreams, nightmares, death.
But not for you, gunslinger. Never for you. You darkle. You tinct.
May I be brutally frank ? You go on.
And each time you forget the last time. For you, each time is the first time."

From what I've seen here - https://allnovel.net/the-dark-tower-the-dark-tower-7/page-32... - the type of language used is modern, despite this story (a quest) being somewhat Arthurian (Roland Deschain is the last of the line of "Arthur Eld", his world's analogue of King Arthur [Wikipedia]). So this use of 'tinct' and 'darkle' (which sound archaic to me), while deliberate, is not a reflection of the language generally used.

Taking the primary senses of these words (where to 'tinct' I attribute a reinforcement of 'darken', given that the word makes me think of (dark) ink, not the colours some definitions give), I get my answer above (you bring death and darkness), but, given the suggestion of a degenerescence followed by rebirth ("You darkle. You tinct. [...] You go on. And each time you forget the last time. For you, each time is the first time."), there may well be another meaning like 'diminish', 'lose strength' , giving tu (t')affadis and, going against the grain, since in principle 'tinct' implies addition rather than removal of colour, tu (te) désépaissis.

Unless, of course, it is meant to be understood 'you darkle (and) you tinct', i.e. you diminish then regrow (the more I think about it, the more I think this might be the best interpretation), donc tu (t')affadis, tu (te) ravives ... (shades ;-) of Alain Souchon and Passez notre amour à la machine / Faites le bouillir / Pour voir si les couleurs d'origine / Peuvent revenir / Est-ce qu'on peut ravoir à l'eau de Javel / Des sentiments / La blancheur qu'on croyait éternelle / Avant ;-). All very Arthurian, the Once and Future King, the Fisher King, The Golden Bough … ;-)