Playing hide-and-seek with Oliver is one of the stranger encounters that Baldur's Gate 3's Shadow-Cursed Lands have to offer—perhaps even stranger than the giant zombie bartender who challenges you to a drinking contest. If you encounter Oliver when first entering the area, you'd probably just assume he's a weird shadow child who enjoys being sneaky, but he's actually a very important part of Halsin's quest.
At the Last Light Inn, you find a comatose Flaming Fist called Art Cullagh babbling about Thaniel, and if you report this to Halsin, he'll set you on the path to dispelling the shadow curse. To do that, you need to find Oliver. While playing hide-and-seek with him isn't necessary to the quest, it does get you a nice magical ring, so here's Oliver's location and how to beat him.
