Who is Lu Junyi from Water Margin and what is their importance?

Lu Junyi is tricked by the bandits into visiting the Liangshan Marsh stronghold. Because Lu refuses to become a bandit and wants to return home, the bandits start rumors that Lu has joined the group. For this reason, when Lu returns to his home, he is considered to be an outcast. He is arrested twice and almost executed before being rescued by the Liangshan Marsh bandits.