Mortal Shell: Enhanced Edition

When I reached the end of my playthrough, acquiring all weapons and shells, and before "entering the cave" for the final boss, I noticed Hadern sitting next to the mounted weapons. He challenged for one final fight. This consisted of two phases against his Axatana weapon.
Once defeated, he surrendered his Axatana and his shell (found in the crypt on floor one). Equip the shell and speak to Sester Genessa just across to access his ability tree.
It's 500 tar to learn his name, then you can view all upgrades. To complete the tree, you must purchase ALL of his upgrades, and one that falls under certain categories. For example, Accretion of Endurance costs 1,000 tar and 6 glimpse, but once purchased, you must also purchase one inner ability for 400 tar and 2 glimpse. The costs vary dependent on the skill but here's a list of each and I'll add the cheapest available inner ability to cut cost.

Accretion of Resolve 1,100 tar, 8 glimpse (inner 400 tar, 2 glimpse)
Accretion of Endurance 1,000 tar, 6 glimpse (inner 400 tar, 2 glimpse)
Accretion of Ascent 1,100 tar, 8 glimpse (cheapest inner 250 tar, 1 glimpse)
Accretion of Inheritance 2,500 tar, 15 glimpse (cheapest inner 250 tar, 1 glimpse)
Accretion of Yearning 500 tar, 2 glimpse (cheapest inner 250 tar, 1 glimpse)
Accretion of Foresight 500 tar, 2 glimpse (cheapest inner 250 tar, 1 glimpse)
Accretion of Dominance 3,000 tar, 20 glimpse (inner 400 tar, 2 glimpse)
Recollection of Knowledge 2,500 tar, 15 glimpse (inner 400 tar, 2 glimpse)
Recollection of Strength 1,000 tar, 6 glimpse (inner 400 tar, 2 glimpse)
Recollection of Death 4,000 tar, 25 glimpse (inner 400 tar, 2 glimpse)

Two tips of advice:
1. I played using Harros shell into NG+ and had many "Glimpse of..." to use on the Hadern shell but not quite enough. If you have glimpses to spare on an older shell, Sester sells Glimpse of Affection (limited supply). It costs 6 glimpses and gives 5 in return but it brought me over the top on glimpses. Hopefully you've got enough extra to not need farming.
2. If you are short on tar but full on glimpse, Sester sells Nascent Tar (limited supply) but at cost of glimpse. Another method is to use Hadern's inner skill under Accretion of Endurance first. When you parry 10 DIFFERENT enemies without dying, your tar gain increases big time!! Smaller enemies would give 22 tar but with that 10 stack, each paid out 133 tar. 6x increase. Combine this with Bronze Bells (limited supply) from Vlas the Catman for 10% more on top!

Any suggestions, especially on other ways to speed up glimpse hunting, drop a comment and I'll add it in!
Good luck everyone!