Power Walker left Silent Walker and Broad Walker behind as he entered Opposer City. He didn't want the person that framed Silent Walker to run away. After all, if he felt that Silent Walker had returned, he might become scared.
As soon as Power Walker arrived in the city, he waited.
The person had to appear in Opposer City eventually.
Sadly, Power Walker couldn't see through the Formation Arrays that isolated the buildings. Because of that, he had to wait until Gravis showed himself openly.
He waited for nearly an entire century before Gravis showed himself to get his second paycheck.
When Power Walker saw Gravis, he locked down on him and remembered his Aura.
However, he didn't act immediately. Power Walker wasn't stupid. If Silent Walker could have a backer such as himself, so could others.
Power Walker wanted to kill Gravis immediately for daring to hurt his favorite child, ehm, junior brother. However, he had to be careful.