Friend (often stylised as friend) is Ghostbur's therapy sheep. Friend is a blue sheep (spawned as a white sheep) that Ghostbur found while traveling with the Butcher Army on their way to detain Technoblade. Ghostbur decided to keep Friend as a pet and brought him along back to L'Manberg, much to the chagrin of the rest of the Butcher Army.
Friend was discovered by Ghostbur on his travels back to L'Manberg with the Butcher Army. It is presumed that Ghostbur either intentionally or accidentally dyed Friend, as no sheep can naturally spawn blue as Friend is.
While bringing back Friend to L'Manberg, the Butcher Army found themselves unable to escort Carl with them as a ransom and to have power over Technoblade, so they asked if anyone had a lead. Fortunately, Ghostbur was using a lead to bring Friend with him, and decided to give his lead to the Butcher Army in exchange for putting Friend in a boat with him along with a nametag so he could name the blue sheep. The Butcher Army then complied and Ghostbur was able to bring Friend back to L'Manberg.
During Technoblade's execution, Ghostbur was walking into L'Manberg when he noticed Technoblade in a cage. He called out to Techno, stating, "Technoblade, Technoblade! I've named him—I've named him Friend." This to which Techno replied, "That's fantastic, Ghostbur. That's fantastic. I'm about to die, Ghostbur." Directly after this conversation, Quackity pulled the lever on Techno's execution chamber.
Later on, Ghostbur would show Philza Friend as well, even giving him Friend's first coat. Phil kept the wool and snuck out during his house arrest in order to feed Friend and make him grow a new coat. When Friend ate grass for the first time, Ghostbur was elated, and Phil brought him back inside.
Phil mentioned that Friend has infinite canon lives  , so Ghostbur would have nothing to fear in case he died. Friend was later accidentally killed with an axe by Ghostbur. Ghostbur repressed the memory and went searching for Friend and where he had respawned.
In order to gain trust with Ghostbur, Dream brought Ghostbur a respawned Friend at Technoblade's cabin. At first, Ghostbur hid Friend in Techno's Cabin, protecting him, until Tommy built his home with a pen for the blue sheep. Friend would stay at the holiday home for several days until Ghostbur moved him back to L'Manberg, where he let Phil look after Friend for a while, before Phil defected from L'Manberg.
After the Doomsday War, Friend had resided in Phil's home, but was killed by TNT. A few days later, Ghostbur had tried to be revived by Phil, Eret, TommyInnit, Fundy, and Ranboo, as well as Tubbo being there "on Skype". Before Phil and Ghostbur recreated the scene during the Manberg vs Pogtopia War, of Wilbur pressing the button, Ghostbur stated he needed to retrieve Friend first.
Everyone had scattered and looked around, and Eret found Friend trapped in bamboo next to the Hall of Fame, after Wilbur's router went out, Ghostbur dyed Friend blue and they continued the resurrection.
Friend got "Skep'd" by Skeppy on accident as a troll, resulting in Friend's third death and respawn.
On April 1st, Tommy and Ranboo retrieved Friend from Dream's vault and left him in Tommy's holiday home before they took him to the Bee n' Boo hotel. Recently, CaptainPuffy searched for Friend and found a Friend by Ghostbur’s resurrection sight. It is presumed this is a fake Friend, but either sheep could be the fake one. 
The unreliable narrator
As Wilbur enjoys breaking the fourth wall as Ghostbur, he raised the issue of the unreliable narrator during the stream. He pondered if Philza actually lied about Friend's infinite canon lives, and that he only said it to cheer up Ghostbur. As such, whether all the found 'Friends' are actually reincarnated versions of the original sheep, or just random sheep dyed blue, remains a canonical mystery.
This is quickly disputed by Philza as well as the other people on the scene, to which in character, Ghostbur agreed, saying that "no one on this server has ever lied", as a result creating a comedic effect. This is especially humorous because Ghostbur's innocence made it so it is perfectly in-character for Ghostbur to have such a response. However, at the same time, this is obviously Wilbur's poking of the fourth wall, as almost every character has lied in some way within the lore. This led to Philza saying that Wilbur is "living within the fourth wall".
Although it was seen on the day that Wilbur was revived, Tommy was looking out for Friend and possibly Ghostbur's belongings as well, Friend does not have a permanent shelter or owner.
Friend likely does have an infinite number of canon lives, as it seems to be confirmed by out-of-character Wilbur.
Along with Friend, Enemy is another influential sheep on the Dream SMP. Enemy is a red sheep that was a prominent symbol and witness at the meeting of Tubbo and Quackity over territory disputes. Enemy was the unofficial cashier of Foolish__Gamer's Gas Me Up, located in Las Nevadas, before they were tragically killed by Sand the dog on June 30th. It is assumed that Friend and Enemy reside together in Limbo.
As a reference to Friend on Dream SMP, Ph1LzA named a red sheep in his hardcore world "enemy". He resides in the blaze empress castle as a pet. At the same time, he also has a blue sheep named "Friend", currently tied to a fence post outside of his home in replacement of the water sheep that was sacrificed to get PewDiePie back into Minecraft. Acquaintance is a yellow sheep that comes from the world of the OriginSMP. Then known as "Piss Sheep," Acquaintance has remained safe and alive.
- Minecraft Wiki - Sheep spawn rates by color
- Phil saying friend has infinite canon lives
-  Phil saying to Ghostbur that Friend has infinite canon lives
- Ranboo trying to figure out if it is friend or not
- Wilbur confirming Friend has infinite canon lives
- Ranboo, Purpled, and Foolish with Enemy.
-  Enemy's death
- Philza showing Enemy for the first time