|“||If I can't go with you, then I'll look out for Cross and my brother to take advantage.||„|
|~ Dream!Sans tells the crew that he'll look out for his brother and Cross|
Dream!Sans is a supporting character for Underverse. While he doesn't play that much of a role compared to the other Sanses, Dream!Sans acts a spy for Ink!Sans's crew, providing them information regarding Cross/X-Event!Chara. When he's on the battlefield, he'll usually target his brother, Nightmare!Sans, for his acts.
Dream first arrives in X-Tale after Cross display a scent of negative feelings. He tries to get in to be shocked and surprised that he ended up joining forces to Nightmare. Knowing this, he screams out of X-Tale, slamming into Ink in the process. He explains the whole deal between Cross and Nightmare, and using this info, he pursuits to find Cross himself, albeit Dream has to be left behind in the process.
With Sans & Underfell!Sans trapped in X-Tale thanks to X-Event!Chara, Dream explains that while he can get them back into Underswap, he requires positive feelings for him to even move out. Since Ink at the time was not showing his emotions, he couldn't get to him, but after Underswap!Papyrus remarks on his timeline, this gives him to power to transport both Sans and Underfell!Sans back to Underswap. Using his spear as a bow, he fires at his brother multiple times, diminishing him to goo. He wasn't able to stop him from killing Underswap!Chara, and he's forced to get the group to flee to Outertale.
Dream dons on a yellow cape with a sun marked on its back, doubling as a scarf, with a red ball featuring a star on its front. His aqua coat stretches towards his blue pants. His shoe-ware consists of golden boots donning two blue stripes, and for headgear, there's a yellow bracelet surround his skull. He even has yellow gloves on him. His spear has two stars, bottom and top, both beneath a blue rod. This can transform to a rod, allowing him to shoot arrow that Nightmare is susceptible to.
Like Error, Ink, and his brother, he can teleport to other AUs, but only when that AU has a positive feeling. This makes it harder for him to not only enter Genocide timelines, but also universes with considerable amounts of negative feelings, such as Horrortale, Killertale, and Dusttale. When he attacks, he transforms his spear into a bow, and fires at his specific target. Since Nightmare is weaken by light, this gives him an advantage over his brother, though it isn't effective to get rid of him.
As a byproduct of positive energy, Dream display a quirky, yet unconfident personality. While he is too talkative and over-dramatic, he does give concern that something terrible could happen and, in response, tries to settle down the issue. For example, Sans begins to feel that something is wrong with Ink, but his conversation is cut short by Dream.
| X-Tale: Cross | X-Event!Chara | X-Event!Frisk | XGaster | X-Tale!Papyrus | X-Tale!Undyne | X-Tale!Toriel | X-Tale!Asgore | X-Tale!Asriel | X-Tale!Mettaton | X-Tale!Alphys