The reason why Lawlessly fearlessly stepped into the arena was because of the additional 10% Detection from his necklace.
This necklace had dropped from a LV20 Wild Boss which had taken the whole of Star Moon Union to defeat. Lawlessly wasn’t the best Thief in the guild, but because he excelled at sucking up to the guild master, he often received better equips when the loot was divided up.
The necklace alone gave him the ability to detect his opponents and strike first. This gave him an advantage against most Thieves because a fight between two Thieves was often dependent on whoever unleashed their combos first.
Lu Li stayed put and observed his opponents.
To be honest, he didn’t see anyone from Star Moon Union as a threat.