Really, ten years of unswerving loyalty to the Plan in the face of everything that befell the Organization is nothing to sneeze at, events of Siren's Port be damned. He knew he saw something in that untested and bratty castle guard all those years ago, and tempering him proved to be one of the best decisions he'd ever made. Xigbar is and always will be important... as a cohort, as a a vessel, as a tool... but Xigbar was the first and that alone is very special consideration. Xigbar was alone with Xemnas in being privy to the plan (perhaps the one really keeping it on track given Xemnas and the other Nobodies) - you have to consider that Papa doesn't reveal his plans to anyone. As much as Xigbar is his property like all his other tools, Xigbar has done so much and held his own weight AND been converted quite well and thus commands a modicum of respect and consideration from the old man.
spoilers if that's still a thing
Really, ten years of unswerving loyalty to the Plan in the face of everything that befell the Organization is nothing to sneeze at, events of Siren's Port be damned. He knew he saw something in that untested and bratty castle guard all those years ago, and tempering him proved to be one of the best decisions he'd ever made. Xigbar is and always will be important... as a cohort, as a a vessel, as a tool... but Xigbar was the first and that alone is very special consideration. Xigbar was alone with Xemnas in being privy to the plan (perhaps the one really keeping it on track given Xemnas and the other Nobodies) - you have to consider that Papa doesn't reveal his plans to anyone. As much as Xigbar is his property like all his other tools, Xigbar has done so much and held his own weight AND been converted quite well and thus commands a modicum of respect and consideration from the old man.