Here is a video to sum up how I managed to be the first ever Guild Wars player to get Legendary Vanquisher fully solo (henchmen, heroes, other players, cons, p-cons, summoning stone and PvE-only skill from EoTN were all forbidden).

How I killed Rotscale HM as solo mesmer:    • Rotscale HM as solo mesmer  

Musics in order:
Sappheiros - Reaching out
Dimatis - Celeste
Grégory Van Praet - Stay Awake
Sappheiros - Embrace
Isolated - Countless
Sappheiros - Distant
Ikson - Youth
Ikson - Bloom