Corwin of Amber, or for that matter any of his brothers and sisters, any of his (only one that I know of) children or his nephews/nieces, his father.... They can shift themselves into other worlds simply by willpower, although it helps to be travelling when doing so. Warning: several of Corwin's kin consider themselves as near to gods as the multiverse needs, and won't hesitate to kill people they see as getting in their way or disrespecting them – or if that person's death is merely convenient (Caine once murdered his own alternate self in order to have a corpse with which to frame Corwin for offing Caine).
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"The Lady of the Lake, her arm clad in the purest shimmering samite, held aloft Excalibur from the bosom of the water, signifying by divine providence that this was some killer weed."
"The Lady of the Lake, her arm clad in the purest shimmering samite, held aloft Excalibur from the bosom of the water, signifying by divine providence that this was some killer weed."