Time passed.
Liam spent most of his days diligently training, pushing his mind and body past any limit it might've had.
Of course, he couldn't actually advance his body, but only perfect its capabilities by improving his mental prowess.
Liam spent more time completing missions than staying within the mansion.
…Truthfully, he did that to avoid his half-siblings and unwanted attention, but when Elsa and Ian began harassing his mother, he needed to stay behind.
'They're not smart enough to do that on their own… Adrian is giving them orders,' Liam figured.
That inevitably slowed down his progress.
The twins realized Liam's body had regenerative properties, allowing them to express much harsher torture upon him.
Quite honestly, Liam thought they were too green… despite being three years older than him.
Most of their torture didn't faze him at all, just annoying him to no end and wasting his time.