Because Blaze lowered her head, not even the holy Phoenix herself and Michael could see Blaze's expression.
And so, when Blaze secretly injected the Yin Flame into the holy Phoenix's chest while the holy Phoenix lowered her guard and looked down on Blaze...
The holy Phoenix didn't even notice it.
She only felt that something cold and warm at the same time entered her chest, and she only thought that it was Blaze's own body temperature.
After all, Blaze was a mutated Phoenix, so it should be normal if her body temperature were strange, right?
The holy Phoenix manipulated the illusion and once again threw the 'death deal' to Blaze in her mind, thinking that after this, Blaze would turn into ashes.
It was a pity that the holy Phoenix's weakness was that she could not see the state of the victims in the illusion and could only vaguely feel when the victims would accept the death deal.