**Water Walking** (Sorcery, dark blue, bottom middle): Gives bonus Ms and AD/AP in the River. Twisted Treeline doesn't have a River. Water Walking was supposed to help with roaming and objective control. Twisted Treeline is too small to need anything more than Celerity for roaming and the objectives are towers, altars and spider. Since capturing altars better fits Domination (I think) I thought the new Rune should be focussed on Towers.
--> "**Lightning Rod**: Gain bonus Attack Damage or Ability Power near allied or enemy towers, adpative."
I thought it would similar in strength to Absolute Focus? It's similarly niche. The effect could differ to be bonus adative damage as well. Or it could also increase allied towers' damage.
Alternatively, if capturing altars isn't reserved for Domination or Lightning Rod has too much overlap with Absolute Focus, the rune could be something else.
--> "**Dark Pact**: Capturing an altar grants bonus Movement Speed and bonus Attack Damage or Ability Power for 15 seconds, adaptive. Only lasts for 6 seconds if an ally captured it instead."
Shouldn't have too much overlap since it gives you a (brief) window of strength you can use.
**The Hunter Runes** (Domination, red, bottom row): You only have three enemies available to kill instead of 5 so you can't get max stacks. I suggest adding the Spider as an option for getting 2 stacks or just 1 and rebalancing them slightly (e.g. Instead of 2.5% healing 3% healing). Or just adjust the UI to say X/3 stacks.
**Zombie Ward** (Domination, red, middle left): Grants a Zombie Ward when you destroy an enemy ward or one of your own expires. There are no wards in Twisted Treeline. Zombie Ward is supposed to help with vision control by playing aggressively, so the new rune should, too.
--> "**Spooky Ghost**: Capturing an altar grants you a Spooky Ghost stack (max. 2). Using Hextech Sweeper releases the ghost(s) to seek out the nearest enemy champion(s) and slow and reveal them for a few seconds.
**Eyeball Collection** (Domination, red, middle right): Grants AD/AP on takedowns and when destroying wards. Again, there are no wards in Twisted Treeline so stacking it becomes harder. You could add things that stack it or reduce the cap and adjust the numbers, but since it's supposed to somewhat interact with vision I'd thought adding another rune that interacts with the trinket and competes with Spooky Ghosts would be nice.
--> "**Vial of Black Mist**: Replaces your Hextech Sweeper with Vial of Black Mist which creates an expanding cloud of Black Mist for a few seconds. Black Mist behaves as Brush. Gain Attack Damage or Ability Power inside of Black Mist, adaptive."
The distinction between brush and black mist is thematic (Shadow Isles) but also a little bit of a gameplay one: It doesn't help Ivern or Rengar and it expands a little as time goes by. I thought of adding a debuff to enemies inside of it Black Mist if they take damage or die, but settled on just giving you a tiny bit of bonus AD/AP because it'd be too complicated otherwise. The Rune also has synergy with Sudden Impact.