Toaru Majutsu no Index Struggle Battle

Toaru Majutsu no Index Struggle Battle (とある魔術の 禁書目録 (インデックス)  頂点決戦 (ストラグルバトル) ), translated as A Certain Magical Index Struggle Battle, is an online social game by Mobage, which was released on December 20, 2012, for iOS devices, Android devices, and mobile phones. Service was concluded on March 30th, 2018.

Promotion
The game was silently announced by Dengeki on October 7, 2012, 3 days before the release of the 5th Shinyaku Toaru Majutsu no Index light novel volume, and amidst news regarding Toaru Majutsu to Kagaku no Ensemble and the Toaru Majutsu no Index Movie.

On November 22, 2012, advanced registration of the game has opened, and those who have registered early will get a chance to attain a limited Misaka Misuzu card. On December 20, 2012, the game becomes open for the public and rare Christmas-themed cards are shown, as well super rare cards announced to be revealed on December 29.

Serial codes will be released for the game when the Toaru Majutsu no Index Movie is released.

On 25 December 2014, it was announced that the second season of Struggle Battle will be coming soon on January of next year, with new systems, scenarios and events.

Gameplay
The game is a social game with the motif of collecting the abilities of the characters from the series, with the aim of becoming the strongest in Academy City. There are bosses in the game scenario, as well as raid bosses for the players to cooperate in beating them.

Similar to the likes of the PSP game, it also features "talking parts", where the narrative of the story is detailed through the interaction between characters with sprites and text at the bottom that is commonly featured in visual novels.

Main page
On the main page as banners that have main events that yields special offerings if the player joins, such as Christmas and New Year events, tasks for beginners of the game, and their partner's status. The player can get all rewards on their giftbox to accept the rewards.

Basic options
The user can play the game against other people in PVP through the use of cards of the characters. The player can make friends, though if the player wants to befriend a specific person, they have to befriend them on Mobage first, before being able to befriend them in-game.

The in-game menu has options for the player to initiate quests using their stamina, or use attack points dueling with other players. The player can initiate quests, which allows them to gain cards and loot, or send out quests on their own to friends. Moreover, the player can also rob others' loot in PVP. When the player collects 6 loots of the same type for a rare card. Furthermore, the player can level up and can give 3 points to either stamina or attack, at maximum on each level up, as well as 3 points for each friend.

Cards
There are two sides of cards: magic side or science side, and cards are divided into three types: Power (力), Think (思), Trick (技).

The player has a battle deck, and are given starter cards. The deck can be edited to modify their defense and attack formations. Each character has a cost, to which sum of all character's cost can be less than or at most, equal to the player's attack. The player can level up cards to increase their stats by fusing them with other cards by using the Strengthening option. This is where the rarity of designation upon each card come from. The tiers of rarity are N, R, HR, LR, SR, and SSR apparently, there are varying tiers for each tier of rarity, as evidence by Rare cards having a plus sign next to them. The cards can be evolved, under the Shift option, by fusing 2 same cards, increasing the card's stats and maximum level, but also increases its cost. The Limit-Over opinion increases the card's maximum level by fusing it with the same type of cards, up to 5 cards at most. There's also a Divider option to decompose cards back to the original cards which are Limit-Overed.

The illustrations of the cards are taken directly from screenshots of characters that are from both seasons of the Toaru Majutsu no Index and Toaru Kagaku No Railgun anime adaptations that are vectorized, from promotional art drawn in the same way as the rest of the illustrations, as with the case of the Mikoto and Index Christmas-themed cards, as well as light novel artwork. The game also reuses the sprites from the Toaru Majutsu no Index PSP game.

Scenario
The scenario tells of a player who has the ability known as Imagine Shadow. A mysterious girl by the name of Usamimi calls for the player, and makes use of the player's unique power through the use of Boosters. She enlists the player to become the strongest in Academy City, but she shows her true colors, wanting magic and esper powers herself, breaking the pact between the magic and science, leading to her being targeted by both sides.

It is an original story written by Kamachi Kazuma.