Synergy

Synergy is interaction between two or more mechanics or cards, to work towards a greater end than seperately they would achieve.

Card Synergy
There are two types of card synergy: direct and indirect. Direct synergy happens when cards directly interact with each other, such as Dwarven Mithril or Weapons being played while a dwarf is on the field. Indirect synergy occurs when two cards interact in a non direct way, such as global buffs and rat hovel.

Direct Synergy
Direct Synergy comes solely in the form of tags, and is very easy to quantify. If a card has a tag such as Dwarf, Dragon, Druid, ect, and that tag is activated, then the two cards have synergy.

Indirect Synergy
Indirect Synergy is a high value relationship between two or more cards, which allows you to do something you normally couldn't. For example, putting a Ikken Hisatsu on Fenrir allows him to kill of 2 creatures, in essence for free. This would have a similar effect to using 2 Ikken Hisatsus on 2 units.

Faction Synergy
While all factions can work together to create a strong deck, some combinations are much stronger than others. For example, Initiative based decks are much stronger as Vikings / Druids or Vikings/Ninjas than Vikings/Warlock, as the Warlocks do not have many initiative based cards.