Titania's Titan Sigil

This spell instantly transports you and up to ten willing creatures of your choice from one Mark of the Titans to another. If the party knows where the Mark of the Titan they are trying to travel to is, then they can appear there immediately without any mishaps. However, if they do not know, they must make a DC 18 charisma saving throw or appear in a completely random place on whichever plane they were attempting to arrive at. Once this spell is used, the DC for this increases by +1 permanently.