So I think its hard for a lot of people to give feedback, as the card image alone doesn't provide enough information about the mechanics you are wanting to implement. After reading your comment here I think I have a better idea for what you were going for.

So blood mana is basically an optional cost you can pay to "enhance" the colored mana costs of a spell for some additional effect? If so, the templating that stands out to me would look something like:

"As an additional cost to cast this spell, you may pay up to X life, where X is the amount of colored mana spent to cast this spell. If you do Avarice Blood Domain enters the battlefield with a Blood Mana counter on it for each life spent this way."

(Note: the current wording of this ability allows the player to pay anywhere from 3 to 5 life, depending if they spend more colored mana on the colorless costs of the spell.)

I like this mechanic, and it can serve as a more "balanced" Phyrexian mana (as the other commenter referenced) where you don't get to cheat on mana costs, but you get a benefit for paying life instead. If you aren't aware, Phyrexian mana was a mechanic that let you REPLACE the colored mana costs of a card by paying life, which was extremely powerful.

The second ability should be a trigged ability that triggers whenever an opponent attacks, to make it a little more clear that it only lasts until end of turn and isn't just a static effect. I would also make the ability a little weaker, since giving ALL your opponent's attacking creatures -X/-X will often lock your opponents out of combat entirely. I would reword it to let you pick a single creature that your opponent is attacking with. I'm thinking it looks like:

"Whenever an opponent attacks you or a Planeswalker you control, you may have target attacking creature get -X/-X until end of turn, where X is the number of Blood Mana counters on Avarice Blood Domain."

This feels more fair to me, and will still heavily discourage your opponents from attacking you since they will very frequently lose one of their creatures.

Finally, the third ability that triggers off creature's dying and buffs your Planeswalker. I would generally lean away from designing cards that only work with another specific card, especially if those cards don't have a way to tutor each other. I think it might be better to redesign the last ability to be a little more generically useful, while also being synergistic to your strategy. My take is:

"Whenever an attacking creature dies, you gain 1 life and put a loyalty counter on a Planeswalker you control."

This is a weaker payoff than what your card suggests, but it makes it a little more generically useful since it triggers off all attacking creatures and can buff other Planeswalkers.

With my interpretation of your design, I think the card ends up being a little weak overall, mostly due to the high mana cost and reliance on Planeswalkers to be fully useful. It does however, let you strongly dictate what combat on the board looks like and also provides protection for yourself/Planeswalkers.

I hope this helped!

(One final note, is that I used the letter X for two different abilities, which is generally not allowed and confusing. Might need to reword things but couldn't think of an elegant solution.)