An infinite mana core.
Eren immediately recognized the nature of his second mana core which was located in the same ethereal space as his first mana core. For some reason, he felt more connected to the infinite mana core than the first one.
While his first mana core had an affinity to lightning, his second mana core didn't seem to have any elemental affinity. As per Eren's knowledge, this had to be impossible because every mana core was born with its wielder's affinity.
This mana core was the same size as his first one. It was also made of Rank 1 mana and was in a gaseous state like the first one. The infinite mana core was like a copy of his first mana core except for the fact that it always kept spinning, never reducing its rotation speed.
'This…'
