Customized BattleMechs piloted by notable MechWarriors from the BattleTech universe, or sometimes notable individual 'Mechs unto themselves, "Hero 'Mechs" are a subgroup of special 'Mechs that were introduced by Piranha Games, Inc. (PGI) in their MechWarrior Online (MWO) and MechWarrior 5: Mercenaries computer games. The concept is a gameplay element in those games, and does not exist as such within the BattleTech universe.
In addition to the stock BattleMech models featured in MWO, PGI introduced Hero 'Mechs for the game as exclusive variants which can only be purchased with real money in what is otherwise essentially a free-to-play online game. Within the game, the Hero 'Mechs offer a unique paint scheme, a per-match C-Bill booster, and a custom hardpoint layout that is different from the stock 'Mech design they are based on.
The Hero 'Mechs created for MWO were originally based on certain named 'Mechs from established BattleTech lore, or the otherwise unnamed 'Mechs of certain famous MechWarriors, especially the "Notable 'Mechs and MechWarriors" sections from Technical Readouts (and here, from the seminal Technical Readout: 3025 in particular). Since the focus was on the 'Mechs themselves, names were created by PGI for 'Mechs that had no individual name in the source material. Other Hero 'Mechs were invented for MWO whole cloth, with no previous mention of either the 'Mech or its pilot in canon.
It is worth noting that while Hero 'Mechs are customized variants of the stock models by definition, the customized configurations of these 'Mechs and in some cases also their names were created for MWO. In the original source(s) naming the famous 'Mech or its pilot there was usually no indication that the 'Mech in question was anything but a regular model, with only a small handful of them mentioned to have been modified in any way. In fact, the entire concept of notable 'Mechs and MechWarriors had arguably been created to showcase the stock models instead of customized special cases.
A selection of Hero 'Mechs from MWO were also among the available variants in PGI's subsequent MechWarrior 5: Mercenaries. Reflecting their unique status, Hero 'Mechs are an uncommon sight in the game's industrial hubs, with a special icon to alert the player when they do appear for sale. Aside from adding additional Hero 'Mechs sold in the industrial hubs, the Heroes of the Inner Sphere DLC introduced a series of specific High Reward Quests which feature exclusive Hero 'Mechs as rewards for their completion.
The convoluted canon status of individual Hero 'Mechs is best understood by considering a "Hero 'Mech" to be a composite concept consisting of its name, appearance, configuration, and fluff (background lore). Each of these aspects should be considered separately, and may be canonical, apocryphal, or outright noncanon.
To begin with, most (but not all) Hero 'Mechs are based on an individual 'Mech mentioned in a canonical source, usually a Technical Readout sourcebook. They are obviously canonical to the extent mentioned in canon.
PGI derives its BattleTech license from the license for BattleTech computer games which is currently owned by Microsoft and is a separate license from the mainline BattleTech boardgame IP that is currently owned by Topps, and licensed to CGL. For the purpose of Canon, Sarna BattleTechWiki considers only the boardgame IP to be authoritative. As such, content from computer games is not considered canonical per se, but apocryphal by default. This applies to any and all information about Hero 'Mechs that was created by PGI, as opposed to originating in canonical BattleTech lore.
However, the descriptive fluff texts for the Hero 'Mechs have been declared fully canonical for the BattleTech universe by then-incumbent Catalyst Game Labs Line Developer, Randall N. Bills, who also penned most if not all of these texts. That means by extension that the 'Mechs as such are canon even when not otherwise mentioned in BattleTech lore, but only to the extent described in the accompanying fluff text. By contrast, their in-game stats and appearance are still apocryphal unless mentioned in the fluff text; and in case of clashes with established BattleTech lore such as anachronistic equipment they are overruled by the established canon, making the overruled parts noncanonical.
(With the release of BattleTech: Legends a number of unique names first introduced in MWO were used, though with configurations and equipment that do not match their MWO counterparts.)
Complicating things further, there is an exception to Randall Bills' ruling: MWO has since published several original 'Mech designs, and Hero 'Mechs were created and fluffed for these as well. Assistant Line Developer Ray "Adrian Gideon" Arrastia expressly clarified that the original designs from PGI are not canonical, regardless of any Hero 'Mechs or Hero 'Mech fluff associated with them.
As a result, their fluff texts are expressly canonical while the 'Mechs these texts refer to are expressly not. To resolve this apparent conflict it could be assumed that the fluff texts can be taken at face value regarding time and events only, but any references therein to the noncanonical 'Mechs should be considered apocryphal, as in referring to "a" 'Mech but not "this" 'Mech.
- In this posting on the official BattleTech Forum by Ray "Adrian Gideon" Arrastia, regarding the canon status of PGI-exclusive 'Mechs for which record sheets had been brought to Mech_Con 2018: "Those sheets are not official and those designs are not canon for the tabletop. CGL cannot use the PGI-created designs, no matter what “part” CGL or its employees play in the creation of the designs. When asked for confirmation, Randall and Brent stated that those were provided by a demo agent and they allowed it *this time only* as part of the hype at Mech_Con."