Because among the four Metal Series Witchcrafts, 'Sharpness Technique', 'Metal Morphing Spell', and 'Metal Barrier', he has already mastered these three.
The only one he hasn't mastered is a Second Level Witchcraft 'Iron Armor Technique'.
From the name alone, it's not hard to guess that this is a defensive-oriented Second Level Witchcraft, which is slightly different from what Rein previously thought: 'perhaps he could find an attack-oriented Second Level Witchcraft'.
And the exchange price at the bottom, 3500 Contribution Points, he happens to have enough. Previously, he handed over that metal arm remnant to the school, and received a reward of 3700 Contribution Points.
However, he only has this many Contribution Points, so he better take a look at the description of this witchcraft first.
With a slight thought, Rein continued to ask: "Can you show me the detailed description of the witchcraft?"
"Of course, Lord Rein."
