Master I

An hour and a half passed, and since my core had begun to accept the energy and it is still doing that.

The energy concentration in the artifact had reached the point where even a person couldn't see who is front of them. 

It is a good thing; these people are protected by the artifact; otherwise, even I don't know for how long my nearly depleted seeds would have been able to protect them against this concentrated energy.

My core seemed to have an insatiable appetite, even after consuming a huge amount of energy. Its appetite did not seem to be satiated; it is still consuming the energies and would continue for some time more.

The breakthroughs of the high Grandmaster lasted for hours; even though I am not breaking through into the High Grandmaster class, I am gaining its power. It could be said, I am breaking into High Grandmaster class if one forgets a little rule-bending.