Affection mechanics (好感度, kōkando?, lit. favorability rating), referred to as relationship figure in the Piggyback guide, is a hidden gameplay element that governs certain cutscenes during Final Fantasy X. Tidus's actions with other party members throughout the game can decide which party member talks to Tidus in cutscenes as well as who throws the blitzball during Tidus's Overdrive Blitz Ace.
How each character is chosen is based upon a hidden "affection" value in the game's code. All of the main characters (except Tidus) have an affection value. At the beginning of the game, all characters' affection values start at zero.
Throughout the game there are times where Tidus's actions can increase or decrease other party members' affection value.
- Whenever Tidus heals a party member, their affection value increases by one.
- Whenever Tidus intercepts an enemy attack intended for another party member using either Guard or Sentinel, their affection value increases by one.
- Whenever Tidus attacks another party member, their affection value decreases by one.
On the field
During times where other party members are spread out across the area, the first party member Tidus talks to will increase their affection value. All other subsequent conversations with other party members in the same area will have no effect on their affection values. The amount at which the affection value increase will vary by party member, as shown in the following table:
Lulu's affinity is the most easily obtained if the player commits to all the available in-field options, save for conversation points. Give or take some options that involve boosting Yuna's affinity over hers, as well as Yuna's over Rikku's, Lulu stands at 48/40, Rikku stands at 24/16, Yuna stands at 24/16/8, Wakka stands at 22, Auron stands at 8, and finally placing Kimahri at 6. Lulu has the highest number of possible affinity points from in-field conversations, committed to all of the 88 possible starting conversations, along with the points possible to conversation options, standing at 220 with Yuna trailing behind at 156, Rikku at 136, Wakka at 102, Kimahri at 88, and lastly Auron at 78.
In Besaid Village (night)
- After speaking to Yuna for the first time, Tidus is asked by Wakka "She's cute, ya?". Replying "Yeah!" will increase Yuna's affection value by eight.
On board the S.S. Liki
- Speaking to Wakka before approaching the crowd of people around Yuna at the bow of the ship will increase Wakka's affection value by four.
On board the S.S. Winno
- Watching the conversation between Yuna and the Luca Goers before eavesdropping on Lulu and Wakka will increase Yuna's affection value by four.
- Eavesdropping on Lulu and Wakka a total of four times will increase both their affection values by four. Speaking to Wakka afterwards will further boost his affection value by four. These must be done before attempting the Jecht Shot or speaking to Yuna after she conversed with the Luca Goers.
- Speaking to Yuna after she converses with the Luca Goers, but before Tidus attempts the Jecht Shot will further boost her affection value by four.
- Based on who has accumulated a higher affection value, Tidus will talk with either Lulu or Rikku after Yuna enters Seymour's manor.
- If Tidus talks with Lulu, when talking to her a third time, she will say, "I shouldn't have to say this, but don't fall in love with [Yuna]". Replying, "Too late" will increase Yuna's affection value by eight. Replying, "You're more my type, Lulu" will increase Lulu's affection value by eight.
- If Tidus talks with Rikku, she will ask, "It's your big chance, huh?" the first time she's spoken to. Replying, "I guess you're right" will increase Yuna's affection value by eight. Replying, "I'd rather have you, Rikku" will increase Rikku's affection value by eight.
- Watching Kimahri leave the item shop will increase his affection value by six.
- When the player returns to Guadosalam later, but before defeating Ginnem's Yojimbo in the Cavern of the Stolen Fayth, speaking with Lulu in the Farplane will boost her affection value by eight.
- After defeating Ginnem's Yojimbo in the Cavern of the Stolen Fayth, speaking to Lulu in the Farplane will further increase her affection value by eight.
On the Thunder Plains
- Outside the travel agency, if Tidus enters before Auron concedes to Rikku, Rikku's affection value increases by eight.
- Speaking to Rikku inside the travel agency before meeting Yuna in her room increases Rikku's affection value by eight.
- After speaking to Rikku inside the travel agency, Rin enters the foyer. If Tidus speaks with him, Rin will ask "Would that be Sir Auron by any chance?". Replying "Nope, wrong guy" will increase Auron's affection value by eight.
Underneath Lake Macalania
- When under the lake ice before speaking to Rikku, if Tidus speaks to Lulu she will ask "We're under the lake ice, aren't we?". Replying "Maybe" will increase Lulu's affection value by eight.
- After speaking to Rikku, but before speaking to Auron, if Tidus talks to Wakka he will ask "Say, you feel something weird in the air?". Replying "Yeah" will increase Wakka's affection level by eight.
There are four cutscenes that are affected by affection mechanics. Whoever has the highest affection value at the time the cutscene takes place will be the one chosen to talk to Tidus.
The first cutscene occurs after Yuna enters Seymour's mansion in Guadosalam. When the party breaks up, either Lulu or Rikku will talk to Tidus. Once the conversation is finished, Tidus can talk to the selected party member two more times for more cutscenes. In case of a tie Lulu takes priority.
The second cutscene occurs after the Crawler is defeated. Either Lulu, Rikku, Auron or Kimahri will accompany Tidus on the Al Bhed machina sled to Macalania Temple. In case of a tie, Lulu has priority, followed by Rikku, then Auron, then finally Kimahri.
The third cutscene occurs on the Fahrenheit, after the party has defeated both of Sin's fins. The party member with the highest affection value will speak to Tidus before jumping off the airship prior to the battle with Sin's Core. In case of a tie, Yuna has priority, followed by Auron, then Kimahri, then Wakka, then Lulu, and finally Rikku. After the cutscene where the party jumps off the airship to attack Sin's Core, Wakka is always the last party member to land, even if he was the party member chosen to jump off the airship first.
The fourth cutscene occurs on the airship's bridge after the battle with Sin's Core, but before the final battle against Sin. The party member with the highest affection value will speak to Tidus after Brother's English conversation with Tidus. In case of a tie, priorities are the same as with the third cutscene.
Additionally, affection mechanics govern who throws the blitzball during Tidus's Overdrive Blitz Ace. Only Yuna, Lulu and Rikku can be selected to throw the blitzball, with Yuna taking priority, followed by Lulu, then finally Rikku in case of a tie. If that character is absent due to story reasons, KO'd, or petrified, the one with the next highest affection level throws Tidus the ball. If all three girls are unavailable, the ball comes out of nowhere. When Blitz Ace is performed underwater, if Rikku's affection level is lower than the other two girls', the ball also comes out of nowhere.
- Final Fantasy X Ultimania Omega, p.428
- Final Fantasy X Piggyback The Official Strategy Guide, p.223