"Flamvell" (フレムベル Furemuberu) is an archetype of FIRE monsters whose effects include burning away the opponent's LP and increasing each others' ATK. Many of their effects are triggered when they inflict Battle damage or destroy a monster as a result of battle. They are introduced in Duel Terminal - Synchro Awakening!! with further support in Duel Terminal - Invasion of Worms!!. They are introduced to the TCG through the Booster Pack Ancient Prophecy, with "Flamvell Commando" as a TCG-exclusive, with further cards coming through the Booster Pack Hidden Arsenal. Aside from being FIRE monsters, the majority of them have 200 DEF, and have support based around that. It is possible that they are used by Bob in Yu-Gi-Oh! 5D's, because he has "Flamvell Guard".
"Flamvell Baby" appears as a character in Yu-Gi-Oh! 5D's World Championship 2009: Stardust Accelerator and in Yu-Gi-Oh! 5D's World Championship 2011: Over the Nexus, "Fiend", "Firedog" and "Origin" all appears in Yu-Gi-Oh! 5D's World Championship 2010: Reverse of Arcadia, and "Archer" appears in 2009.
A Deck using the "Flamvell" archetype will essentially be using FIRE monsters, most of which have 200 or less DEF, and their trump card, "Rekindling", can get you up to 5 monsters at once. This could lead to various Synchro Summons, or if you have a "Flamvell Archer" handy you can tribute it, "Flamvell Baby", or "Flamvell Poun" in order to add 800 Attack to each one giving you a total of 3200 extra attack points.
Since "Rekindling" and "Flamvell Firedog" plays a large part in most "Flamvell" Decks, cards like "Vanity's Ruler", "Vanity's Emptiness", and "Fossil Dyna Pachycephalo" kills this deck type. In addition to that, a Macro deck will destroy the strategy by making it impossible to use "Rekindling"'s effect to its maximum extent. "Prohibition" or "Armageddon Designator" (the latter in Mirror Matches) can also prevent the use of "Rekindling", making it much harder to win. "Necrovalley" and "Silent Graveyard" can also now stop "Rekindling" in the TCG since TCG/OCG rulings merged.