Your only character that shiws any history of attempting the mission is your titan, with two runs, and they were both solo attempts. Your titan is still under-powered for the heroic mission. That's not to say that it can't be done, but you will have a much harder time, and I wouldn't recommend using swords, as having to get close enough to use it will probably result in you getting killed first. Instead, try using a bow, with overload mods, and stun it from a distance, then shoot it with rockets while its stunned.