Lero-Ro

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He serves as the Examiner of the Second Floor, acting as the instructor for the Light Bearer position.
Lero-Ro is quite elderly, older than Yuri Zahard, whom he encountered when they were both Regulars. Yu Han Sung awkwardly refers to him and Quant as a "Set Menu."
He appears to be well-known, since his profile is available on the network used by Light Bearers. It took him over 300 years to ascend the Tower.