Judging from the description of its Ultimate Move, however, even the hint of "Fusion" did not seem to be usable directly as "Fusion."
It needed to go through the process of [Summoning] in order to complete the Fusion between [Radiant Hero] and [Radiant Dragon].
That also meant that [Blue-Eyes Ultimate Dragon] could not be used as the [Mount] for Fusion.
Because Dark did not yet possess the Magic Spirit Card of [Blue-Eyes Ultimate Dragon].
Of course, all of the above depended on [Sacrificial Blessing] actually having a Fusion effect.
So they first had to test the true effect of this Ultimate Move. "In that case, let's test it."
Without hesitation, Dark went outside the laboratory to begin the test.
As they walked, he briefly explained the abilities of [Hidden Sage of Light] so that Ergane would understand.
Then, he began to summon [Hidden Sage of Light].
[Hidden Sage of Light] possessed [Concealment Mode], which allowed it to disguise itself as a three-star Magic Spirit, but [Concealment Mode] naturally only took effect after it had been activated.
Thus, its first summoning still had to be an ordinary Tribute Summon.
Dark first summoned a sacrifice, then used it to Tribute Summon [Hidden Sage of Light].
As the Tribute Summon circle emerged, [Hidden Sage of Light] materialized amid a radiant glow.
A distinctly powerful Light Attribute divinity could be sensed from its body. After a moment's thought, Dark ordered it to remove [Sage's Robe].
The concealment abilities of [Hidden Sage of Light] were basically all concentrated within that [Sage's Robe].
While it wore [Sage's Robe], even if one tried to peer at its face, all they could see was a sea of light.
Only by removing [Sage's Robe] could its true appearance be seen. Since Dark was considering granting it intelligence, there was