Ellivere herself creates Virtuous enchantments, giving creatures +1/+1 for each enchantment you control - a potentially massive buff
One colour will mean all of your lands will let you cast the spells you have, but adding a second colour dramatically increases the pool of cards you can choose from
HeiHei is the best card in the Might and Magic dec k, returning to hand each time the Dreamborn is banished
The only drawback is the color-intensive mana cost, but decks with robust mana bases can handle that
If the second ability triggers multiple times in the same turn, perhaps because there were multiple combats, you will be able to play that many additional lands
The card stock is great, the art is vibrant, and unlike some other proxies Ive had over the years the text is all all clear