Joined Your Party

""... joined your party.""

Stock phrase in role playing games, also rendered as "Joined the party". In Japanese, this is typically "__が仲間になった" ("X became your Nakama!". Sometimes rendered "__がなかまになった" in games on older hardware or for younger audiences.)

Common enough that only examples that are played with should be listed.

Adventure Game

 * Strong Bads Cool Game for Attractive People: 8-Bit Is Enough does this, being an Affectionate Parody of old videogames. ___ HAS JOINED YOUR PARTY!

Role Playing Game

 * Shadow Hearts series has a Running Gag that Roger Bacon pretends to join your party (complete with 'Naming screen') but never actually does it.
 * Chrono Cross's messages are personalized for each character's accent/verbal tic/gimmick. "Marcy, like, joined your party!" "ZOAH JOINED YOUR PARTY." "Greco tagged into your party!" "Razzly joined your party-hee!" "~Doc joined your party, dude!" "Grobyc-joined-your-party."
 * Super Mario RPG has Bowser joining your party with the announcement, "Mario and his friend have joined the Koopa Troop! (or so they're pretending)"
 * In the first Paper Mario after you reach the top floor of Boo Mansion, Bow joins your party, as the text box notes, "like it or not!"
 * In Paper Mario: The Thousand-Year Door, after you beat, Vivian is said by a text box to have "really joined your party now!" Also, in Chapter 5, when Flavio accompanies Mario to the entrance to the Pirate's Grotto, a message appears stating that "Flavio will join you for a short time" even though he only follows Mario around and does not act as a partner. Most of the other tag-along characters join without a message of that sort.
 * Skies of Arcadia announces that "Drachma joined your party... again" after said character rejoins for good after dropping in and out of the party several times in a short timeframe. Much later, one crewmember brings with him a twist on the "X joined your crew as a Y" message: "Pow joined your crew as a Jester... of sorts."
 * In Final Fantasy IV, a minor NPC joins your party at one point even though it's full. But before you regain controls he already turns out to be a monster in disguise.
 * Dragon Quest VIII has the characters do a little pirouette and bow to cutesy music when they join your party.
 * In Persona 4 if you return to a dungeon (that happens to be built entirely as a homage to 8 and 16 bit jRPGs) at one point and add Yosuke to your party he will comment "Yosuke joined your party! ... or something like that, right?"
 * When someone joins your party in Fallout 3 and Fallout: New Vegas, a pop-up message appears telling you so. This was absent in the first two games of the series, when potential companions would just start following you after their recruiting conditions were met.
 * In Knights of the Old Republic, one character who will later join your party has some rather awkward lines about how if you help him and allow him to "join with you" he'll help you out.

Turn-Based Strategy
"[Rozalin] is bound to you by the terms of the ritual. Deeply swayed by Adell's manliness and cologne, [Yukimaru] joined the group. Beauty Queen [Etna] is stalking Adell. Under the condition of three square meals a day, [Overlord Laharl] has joined the group."
 * Disgaea has at least two people who join your party without your consent, and a few more who are actually enslaved by Laharl.
 * Disgaea 2: Cursed Memories plays with this for most of the main characters, to whit:

"Tink was enrolled as a student while still unconscious. Mao has received the most badass Notebook ever."
 * Disgaea 3: Absence of Justice continues to play with this for its downloadable characters:

"Warden Axel was forced to join your party, but he's so weak and useless that he won't fight in the battles."
 * At one point early in the game you get the message "Raspberyl ended up traveling with you" however she doesn't officially join your party till later.
 * And in Disgaea 4: A Promise Unforgotten:

Comics

 * In Scott Pilgrim, of course. On the first pages of the fifth volume, Scott and his friends are at Julie's new apartment's Day of the Dead party. Scott and Ramona encounter her fifth and sixth exes, the Katayanagi twins, experts on robots and technology. When they challenge Scott to a fight, a robot goes inside and, just... joins the party.
 * Which happens in the video game as well. "Robot-01 joined the party!"

Web Comics

 * Early in Errant Story, Meji met Chris, a deeply stupid young man who is a parody of jRPG protagonists. He invites her to join his party, and she responds by casting an invisibility spell and slinking away from him.
 * A Big Damn Heroes moment during Penny Arcade's "Armadeaddon" arc: "FRUIT FUCKER has joined the party!"