I have tested it in a standard CC deck with slight modifications to fully support it, and it has quickly become one of my favorite cards. All this about it not being splashable is nonsense. The targets for it that I run (not including flips) are: Sangan, Treeborn, 2x Reaper, Exiled, and DDWL. Also, if you have Tsuki, pulling flips may not be totally useless in 100% of situations. Tributing for a Monarch or using Exiled are the two best ways to trigger it.

Yeah...basically bring out the Frog with it and Tribute it next turn (assuming it lives or dies and is able to come back).

Reaper and Exiled are the two best things to combo with Last Will. The Frog is number three on the list.

I suppose...people usually tend to go for the Reaper though with its "indestructable" defense (unless a Tomato is killed)

I'd have to disagree with that previous list. One of the drawbacks of Treeborn is the difficulty in getting it in the graveyard without you taking a ton of damage or getting it removed from play. Last Will greatly overcomes that drawback, thus making it the best monster to fetch with Last Will. Spirit Reaper and Sangan are my other go-getters.

Yeah...since Last Will can Special Summon the monster in Defense Position (another reason why Reaper is another favorite to retrieve)

I have to agree with what most people are saying about reaper although when i tested this in my monarch control i found my self taking treeborn most of the time, the one problem with treeborn is that you only really have sangan to search for it so having another card that can find him is really useful. Also its really easy to meet wills requirement when you are sacrificing for monarchs and brutal when you bring out a reaper after a bit of field clearing with zaborg.

If you are running a more dedicated Monarch Control, Treeborn is the obvious choice. In many other cases, Reaper, Exiled, and Sangan are good choices as well. Also, for the record, I don't recall EVER using Last Will to bring out a Reaper in defense mode. If I'm using this card to bring out Reaper, its so I can grab a card from my opponent's hand.