Sold mine today, I got it for 1 mil so I listed for that price. In Fairy the price fluctuates between 900k to 1.1mil. I decided to go with he Onimaru.
I'm rather disappointed with this GK. The +2 STR is nice but the Onimaru's attack bonus more than makes up for it. The Nukemaru's Firesday Dmg bonus is nice but I wouldn't hang on to it for that. The +2 bonus is what gets people to buy this for 1mil. My suggestion, go with the Onimaru until you get the Ushikimaru Rare/Ex and free.
i just bought this GK... and all i gotta say is GGRRRRRRR >.> lol... price stayed up 1M for a long time.. one day i decide i want a new GK .. so i go to the AH and i bid 700k... it says.. you buy a nukemaru for 700k.. i was like .. wohoo!!.. i check the AH the next day.. 2 had sold for 500k... and if u go check it now... last one sold for 290k... if only i had waited 3 days.. >.>
It is from the high level altepa garrison I believe, and it does good damage by itself. STR+2 is always on, and on firesday it just tears things up. Also, the blade is indeed blue, same as the rare/ex avengers or the joyeuse. I have one, and consider it the ultimate "show off" great katana. Unfortunately if i ever quit samurai I doubt I will be able to get rid of it, what with it being near a million gil on my server and 2 are already on the AH.