Based on River of Tears and the Tainted lands.

Alright, first of all, it being a forest mean it innately has the ability to tap for green mana. So you can tap it for green even if you played a land that turn, making it strictly better than a forest (Which is something that design always tries to avoid -- if you make something strictly better than a basic land then it's an automatic 4-of, which is one of the major no-nos of card design in general). It also seems more complex than it really needs to be(Why does it tap for colorless? Why do you need to control another forest to tap for blue or black?). Overall, it feels like you're putting too many things on one card.

Hi, whoa, hello! I'm making a draft cube that encourages a strong commitment to a main color plus one or two splashes. A friend suggested putting a cycle based on either River of Tears or the Tainted lands into such a cube.

(discussion is here: http://riptidelab.com/forum/threads/mana-base-brainstorm-thread.915/page-3#post-51188)

I slapped this together as an example of trying to mash both those ideas together, along with making it a triland instead of a dual so that you don't need as many cards to fill out the cycle.

Thanks for the thoughts, though, I didn't realize that about the Forest subtype! I'll slim it down some and see what Onderzeeboot says about it.

If the land doesn't require the presence of some other land, Tained-style, then I might be forced to have the land enter play tapped, which I definitely do not want. But, because the land does currently require another land in play, it needs to tap for colorless so that it can do something when alone.

Though at the moment, as you see in the thread, I'm honestly planning to just do a cycle of Tainted-style lands and abandon the River of Tears angle for now.

I really didn't expect to get comments on this site, so thanks again!

Yeah, sticking to one or the other seems like the best idea. I don't really know enough about your cube to offer up further advice at the moment, at least not without serious thought. Though maybe for variety, you could do a bit of both (i.e., river of tears style duals for allied colors/shards or whatever, tainted style lands for enemy colors/wedges, etc.).

I will note that "add to your mana pool" neither functions nor means what you think it means. It's trying to add hybrid mana to your mana pool, which just doesn't work in the rules -- it can only appear in costs.

And yeah, it can be a bit of a crapshoot whether someone comments or not, but they do so often enough for it to be somewhat worth it to post ideas here.

I think that, officially, if an effect somehow adds a hybrid mana to your mana pool, it adds one mana of either of its colors. However, cards never add hybrid mana. It is impossible for hybrid mana to be in your mana pool, just as it is impossible for generic mana to be in your mana pool.

It does work - it can happen via Elemental Resonance or Charmed Pendant - and it does exactly what you'd think. You choose either blue or black and that mana goes into your pool.

Yes, this does mean Graven Cairns could have been written much more succinctly as ", : Add to your mana pool." But I assume Wizards think that'd be confusing so they haven't done it.

A rule has to exist to fix the sort of situation where hybrid mana (or Phyrexian or whatever) ends up getting added to your mana pool, but it's against the more meta rules of design to intentionally add anything to your mana pool that isn't . That's not acceptable.

Today I learned. I was just trying to save a bit of text, because I've seen filterlands described as generating ; good to know!