Basic idea is as the title mentions says. A game mode where you need mana to summon structures.

Pros

-moves are more deliberate and purposeful.

-Lowers skill floor, you can take more time and pay more attention to your gestures.

-promotes more "dynamic" playstyle as it would be more economic to use other player's structures against them.

-could add different mana costs to shift stones, giving more options towards balancing.

-Could add game mode specific shift stones for game mode (max mana, mana regen, mana efficiency)

Neutral

-Anti-spam meta. Punishes players that have taken the time and effort to practice quick, efficient, and accurate gestures. But also helps new players not simply get out paced by veterans.

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Cons

-Could possibly limit more complicated multi-structure combos depending on mana costs/mana pool

-Host advantage when countering/parrying, though that's already the case. This game mode could exacerbate the issue.