*ZZZZ*
Lannister grinned, watching the portal humming with raw power.
A few weeks of experimentation passed, and Lannister found his way into the mirror reality. He kept coming back, drawn to this dungeon entrace since his teleport mana resonated with the strange energy linking it to the mirror reality.
It was purely coincidence that he chose this dungeon entrance to toy with, this dungeon that kept the mirror reality in place and aligned with the real world. It was like a bearing, or an anchor in reality, holding its existence in fixed space.
Responding whenever Lannister tested it, he continued to probe and experiment until it finally cracked open.
A shimmering silver portal circled with chaotic violent energy, a tunnel directly into the mirror reality.
Normally portals did not hum dangerously or have such luminous crackling energy around its edges, but sensing some stability in his new portal, he eagerly tested it.