Keep those fires alight
The most important thing to keep in mind about the Fire powerset is that your abilities are dependent on setting the bad guys near you on fire -- and keeping them burning. If that's not happening, then you're likely going to wind up in trouble in very short order. For most people who have played Fire to endgame, this is a no-brainer, but for those who are just venturing into Fire, it needs to be said. Keep those bad guys burning!
I'm a firestarter
In all the reading I've done leading up to endgame, there simply hasn't been a consensus on exactly what a Fire tank's load-out should be. Some builds are more a matter of the person's own tastes and take into account a player's skills. Still, there are some powers that appear frequently among people posting builds for their utility. In terms of my own playtime, I've tested these powers and have found them to be incredibly useful when you're trying to keep the bad guys focused on you.
Meteor Strike: Without even talking about the power's abilities, I can say this is just a purely fun power to have in the first place. Bad guys pissing you off? Drop a giant flaming rock on their heads. Want to get the attention of a group? Pick the meteor up and toss it -- or run over and beat someone upside the head with it. Not only is it purely a fun power, but it also inflicts the Burning DOT, which will help set off other powers.
Backdraft: As a case in point for Meteor, Backdraft will both heal you and increase your max health when you use it against enemies suffering from the Burning effect. While that's pretty cool in itself, my favorite part as a tank is that it pulls all enemies closer to you, which makes it easier to keep aggro and gives other party members the chance to go AoE crazy on one area. Set 'em up and knock 'em down!
I should probably also note here that I've seen some players mention taking Low Pressure from the Flight powerset to pull mobs in close. I've tried Low Pressure out, but I felt that Backdraft had more utility between the two. After all, I can use Backdraft to get a heal as well as to pull mobs in versus just pulling them in. Low Pressure seems like a wasted power point when you could be spending it on the Innate powers at the base of the Iconic Powers tree, which will help boost overall stats.
Not only does this do a great job of causing mob pain due to boosting critical strike chance and damage, but it also provides an additional heal for you. Since Fire is based so heavily on the ability to mitigate damage by healing the beating you're taking, I really like to keep an eye out for powers with the addition of +heals. Aside from that, Fiery Weapon has a fairly low power cost and can be used heavily to keep mobs glued to you.
Wildfire's nice for a knockdown effect if you're up to your eyeballs in bad guys and need to take a quick breather. It's also useful if you find that not enough nearby enemies are on fire. Wildfire jumps from anyone who is Burning to any other non-Burning mobs nearby, adding to your ability to draw aggro. Be careful, though, because you might find yourself with a bit too much attention all at once.
This is my "oh crap" power. Not only does it provide you a nice heal, but it's a heal that can be used while you're controlled. If you find yourself getting smacked around very hard and there's no heal coming, this can really save your butt. Aside from that, it appears to cause some pretty nice aggro as well.
From there, I tend to swap the final power around as I'm not entirely married to any one particular power as yet. Sometimes I'll go for something more direct-damage; at other times, I'll swap in for an AoE damage or another heal if I'm afraid of going down fast. I've seen everything suggested from Spontaneous Combustion
(boom!) to Inferno
(offering both Burning on mobs and Immolation on all friends, helping to reflect damage) to Absorb Heat
(stun and heal). If you're a Fire tank and you find yourself using something completely different from the above five powers, please do leave a comment and tell us about your build choices!
Ultimately, I believe the best build for each player will take into account skills and powers as well as the needs of your group. I'll freely admit that I'm still learning -- and suffering defeats here and there. However, as in any MMO, half the rush of endgame content (at least for me) is the fun of figuring out an optimal strategy for the group I'm in, no matter how off-the-wall the strategy might seem at the time.
Every week on Saturday, strip off the mask of your Alter-Ego and soar through the world of DC Universe Online with Krystalle, then catch up with Larry on Wednesdays as he showcases the superhero game on the Alter-Ego livestream. Send up a bat-signal to ping Krystalle or Larry with your burning questions. (Packages wrapped in green with a purple bow will be returned unopened.)