Chapter 111 The First Mage
Blending a Magic Potion for an Upper Rank Supply Flame Knight isn't difficult; the challenge comes from the scarcity of the key ingredient, as there is no surplus of Superior Calamity Hearts available.
To step off the path of a Supply Flame Knight, Lind needs to prepare a Superior Calamity Heart to successfully ascend to an Upper Rank Supply Flame Knight, and additionally, a Hero Tier Calamity Heart.
In other words, the most sensible progression for Lind is to ascend his Sun's Testament Great Knight path, as this would make it easier to branch out his "Talent Skill Tree".
However, he could first consume the Magic Potion prepared in the earlier phases to tune his body's adaptability to its best and then, once in possession of the Superior Calamity Heart, have Mico blend the Magic Potion directly.
This could greatly shorten the time required.