I would just like to know how one would go about memorizing long song lyrics. 10 minute + epics for example.

More specifically something like this: (Crystallised)

http://www.darklyrics.com/lyrics/haken/restoration.html#3

This song is about 18 minutes and the lyrics dont really repeat. There are some motifs here and there that repeat. But the song just keeps progressing throughout.

The longest songs I have ever memorized were like 2 mins short songs. Lyrics don't stick to me like music. I have a sister who can memorize lyrics after listening to songs only a few times.

That's how it is for me when it comes to melodies/rhythms/music.