3. Win It
A startlingly obvious reason for Undertaker to enter the Royal Rumble is so that he can win it! WWE in recent years has struggled to top Undertaker's matches at Wrestlemania. His streak is now the real main event and any matches that follow have at times succumbed to being underwhelming. Why not just go full out and have Taker win the Rumble so he can close the Mania show? It makes sense. Especially if Undertaker is indeed to retire this year, he absolutely has to go on last at Mania. The best way to facilitate this would be to have Taker win and challenge the champion. That is the most fitting way for him to bow out, making his last stand in a closing championship match on the grandest stage of them all. If Randy Orton is still Champion then it would be a very compelling bout to watch. Orton was the young up and comer when he faced Undertaker at Wrestlemania 21. The Legend Killer failed to win on that night, but it was a very good match. This time around Orton would be coming in as a veteran himself, and the added stakes of the streak versus the title would make it a mouth watering prospect. One last Rumble win and championship main event berth at Wrestlemania is truly befitting of The Undertaker legacy.