Lumbridge guards were monsters found in Lumbridge where they defended the town from Giant rats and goblins. One fought the goblins to the south of the River Lum, another fought the ones in the forest north of Lumbridge Castle, while another fought the giant rats west of the castle. When they were low on health, they ate to heal.
These were the only guards in Lumbridge that could be killed, and they were the weakest type of guards in RuneScape. With the release of RuneScape 3 and the Battle of Lumbridge, they were made more numerous, unattackable, and no longer fight goblins and rats (with the exeption of 2 guarding the bridge east of the Lumbridge Castle).
The drops obtained from these guards were aimed towards helping out newer users as they levelled up their combat skills. The drops could also be sold for a mediocre amount of money, which could be potentially useful for newer players. Training solely on them was not recommended as there was only one in each area and they are often fighting other monsters.