Hidden Aspect of Twin Fists

[JubeTheNoob]

I am struggling with an issue affecting unlocking the hidden aspect of the fists.
Here are the things I have done so far to try and get them:

1. Have over 5 titan blood invested into the fists
2. I have fought Asterius with the fists equipped and he gave me the "you're gonna fight me with bare hands" dialogue
3. All other hidden weapon aspects are unlocked.
4. I have done over 40+ runs with the fists and other weapons trying to get Asterius to say the next line of dialogue to unlock the aspect but he keeps on giving me one liners about me being short.

Please can someone assist me as I really don't want to start a new save to get this last achievement.

Thank you!