Rudra no Hihou ("Treasure of the Rudras") is a scenario-based JRPG for the Super Famicom and the last game Square developed for a Nintendo console for six years. It was later added to the Virtual Console for Wii in 2011 and again for the Wii U Virtual Console in 2015. The game has yet to be officially localized into English, but translation group Aeon Genesis put out a fan translation in 2006.
The game sees four heroes - each of which is named by the player before starting - who embark on different quests relating to halting the arrival of the Rudra: a deity of destruction that is fated to appear every ten thousand years to eliminate the dominant race and replace it with a new one. The human race's Rudra is due to appear, with various portents that spur the heroes into action. The first three heroes' campaigns can be played in any order, but all three must be completed before the fourth becomes available. In each campaign, the selected hero and their party will occasionally meet other parties mid-way through their adventures.
The game uses a time limit system - the Rudra is fated to awaken sixteen days after the start of the game - but time only moves forward after the player has made progress with the story. Sleeping in inns or grinding outside of town won't move time forward. Each of the four heroes' campaigns are concurrent, and events that occur on specific days can be observed by multiple parties.
Rudra no Hihou has a traditional JRPG turn-based combat system where characters attack and perform actions based on a turn order defined by their stats. Each character has a set class and progression, as well as specific equipment types they can use. Some characters have limited equipment due to their race also, such as the Giant, Ture. In many cases, equipment for non-humans cannot be purchased in stores and needs to be found in dungeons instead.
One of the game's novel features is its spell system: players are able to create and perform "Mantras" in combat. Mantras are built by typing words into the game engine, each of which then turns into a spell with different effects, elemental types and spell cost. Most words create low-level spells with high costs: the path to creating better Mantras is through learning prefixes and suffixes and attaching those to pre-existing spells for additional effects, such as targeting multiple enemies at once. It works in a manner similar to the "Fire, Fira, Firaga" system of stronger magic spells in other RPGs.
The player can learn these spells and affixes by talking to NPCs and reading books and signs in the world. The player is able to save a large but finite number of Mantras in their spellbook, editing ones they already have if they find superior versions. Mantras don't need to be "learned" by the characters in order to be used, and so players can simply recreate their best Mantras for other parties once they switch over.
For years, the Mantra system was the one feature that impeded the creation of an English translation patch.