Because it just won me a tournament [Heavenly Wolf King Blue Sirius]

[Expelsword]

[img]http://images.wikia.com/yugioh/images/c/c7/SiriustheBlueDogStar-VJMP-JP-UR.png[/img]
"1 Tuner + 1 or more non-Tuner monsters
When this card is destroyed and sent from the field to the Graveyard: You can target 1 face-up monster your opponent controls; that target loses 2400 ATK."

Well, not an actual one, just an online one, but still
[spoiler='Wheeee']So it's Laval Quasar (@5400) against OOPArt. (@6000)
He has a [url="http://yugioh.wikia.com/wiki/Wind-Up_Arsenal_Zenmaioh"]http://yugioh.wikia....rsenal_Zenmaioh[/url] out in ATK mode, along with a Crystal Bones in DEF mode, and 1 facedown. I draw and use Rekindling to get out Catastor (for Zenmaioh), and Dual Slasher (for Bones) leaving me with an unused Handmaiden (having lost my Dragon to a Warning). I go to attack with Catastor and he Compulses it, so I have to settle for dealing a bit of damage off of Dual Slasher and leave his Zenmaioh out. I decide that I don't want to lose my Handmaiden, so I Synchro into this guy in DEF mode and end my turn. He uses Babylon to get out Crystal Alien and then attacked and killed Sirius, bringing Zenmaioh to a paltry 200 ATK.
Thanks to a handy dandy Gold Sarc from a few turns ago, I wind up with another Rekindling. I use Dual Slasher and 3 Handmaidens to go from Dragoon to Black Rose to Scrap Dragon with a Magma Cannon left over. I use Scrap to blow up Alien and ram into the superbly weak Zenmaioh, attacking with Magma for game.
TL;DR: Rekindling is broke, but Sirius made this kill possible.[/spoiler]

So discuss underused Level 6 Synchro. He's not bad, even if Brio is better.

[Shradow]

Well...

I can say I quite like its art.

[Canopy Star - Eon Sphere]

Are those his hands? Dammit Sirius, if you were a bear I could have made all kinds of jokes.

Umm, it's alright, but I doubt any deck would actually run it over [s]Goyo[/s] [s]Brionac[/s] whatever Level 6 Synchro people use these days. I'm more of an Xyz person, myself. I guess it's more outclassed by Synchros of other levels, like Black Rose, Catastor and Scrap. Just because it's a decent Level 6 doesn't mean everyone will want to use it.

[Shradow]

Besides, we all know who [url=http://yugiohaddctions.webs.com/GaiaKnight,theForceofEarth5DS1-EN-SR-1E.png]the best Level 6 Synchro[/url] is.

[Cute Rotten Yoshika]

ive used it to decent effect before. i got rid of a high priestess of prophecy with it aha. its not bad. if youre making a synchro centric build its worth seeing if you have a spot for it.

[Toffee.]

I remember maining this in (early) Firestars.
Chouten into this, and then have something that; Regardless of destruction(Except Solemn cards/Bottomless), drains another monster of 2400.
Pretty amusing card, really.

[Darj]

My first choice of generic Level 6 Synchros, except when the Deck focuses in Dragon Synchros or has Shadow-Imprisoning Mirror in the side. It might have 200 less ATK than Gaia, but its effect is something the opponent must be careful of.

I believe his attribute works in his favor, giving him a place in DARK and Chaos Decks. The type is more of an added bonus, which allows him to be benefited by the Firedances and Horn of Phantom Beast. However, there might be no space for this in Firestars with the recently announced Beastlord Vulcan, also a generic Level 6 Synchro.

[newhat]

Not a Debris target so the only way I think he might be useful is in some kind of T.G. Beastdown hybrid. Chouten has bigger fish to fry.