Principal Game Designer  

What do you take into account when you decide not to add mana to a champion? (As a Talon main, it’s annoying to have to return to base after being poked by a Katarina, Zed, Vladimir, etc.) 
By default we give champions mana as an attritional element that does two things:
  1. Every spell cast has an additional decision point: “Is this cast worth the mana?”
  2. We get a long-term attritional element that forces you to periodically return to base.
That said, there are a variety of reasons we might choose to omit mana from a champion’s kit:
  1. The champion has a different important resource they need to use (like Gnar’s rage). With more recent champs, we also have the option of adding a “second resource” that lets them still have mana, such as Jhin’s bullet system. This is used when the champion pattern or core concept relies on a new/different resource than mana.
  2. We actually don’t want the attrition risk of casting spells, going for more of an aggressive “spam casting” model (like Riven and Garen). We may use this model in cases where a champ has to take risks to get an advantage, so squishy melee or short-range fighters are the most common candidates. In contrast, a poke mage like Ziggs would be a very bad choice here.
  3. We want to emphasize another attritional element, like health costs for Mundo and Vlad. Over time, we haven’t found this to be a particularly exciting or interesting direction, so we haven’t been making many new champs with the health cost model. Significant health costs make the casting risk more immediate than long term, which too often would lead to not casting.