Here's Gwen–a champion that has two keywords (Quick Attack and Hallowed) and three pieces of game vocab (Attack, Drain, and Level Up).
In a tiny amount of space, here's what the card tells us about Gwen's abilities before she levels up (Note: Only Champion Cards level up):
- Quick Attack: When this 3|4 Gwen attacks, because of her Quick Attack, she deals her 3 damage first, before her blocker can strike back (normally, strikes between attacker and blocker happen simultaneously, but Quick Attack prioritizes the attacking unit). If her blocker has 3 Health or less, she can successfully slay her blocker. Because her blocker is now dead, it isn't around to deal damage back to her, so Gwen leaves combat unscathed; her Health remains at 4.
- Hallowed: When units with Hallowed die, for the rest of the game when allies attack, the first (leftmost) attacker (regardless of whether they have the Hallowed keyword) gets "hallowed" this turn–that is, they will get +1|+0 that round, for each allied Hallowed unit that has died this game. For example, if 5 ally units with the Hallowed keyword have died so far this game, the leftmost attacker will be "hallowed" with +5|+0 that round.
- Attack: Because the highlighted Attack: text is present, an ability is triggered when Gwen attacks:
- Gwen gets the same additional Power as the leftmost attacking ally's bonus Power from Hallowed. Example: If 5 units with Hallowed died this game, and Renekton is in the leftmost attacking position, Renekton will get +5 Power as the leftmost attacker, even though he doesn't have the Hallowed keyword. Because an ally is getting that buff, Gwen gets it too–she's attacking as an 8|4 unit that round.
- Drain: When she attacks, she also drains 2 from the enemy Nexus. That is, she deals 2 damage to the enemy Nexus and heals the ally Nexus for the same amount.
- Level Up: Every champion has their own unique condition to level up in game. In Gwen's case, it's when she deals a total of 10+ damage.
Numbers and icons along the border:
- Top left number in the blue circle: The mana cost to summon a card from your hand to put it in play on the board. Summoning Gwen costs 4 mana gems. (Note: In LoR, units can do combat in the same round that they are summoned.) See Mana.
- Top right icon: The region the card belongs to. Gwen belongs to The Shadow Isles. Your deck can contain up to two regions. (Note: Origins on regionless Runeterran champions can bend this rule.)
- Bottom numbers: The unit's attack Power (damage-dealing stat) is on the left and the unit's Health (defense stat) is on the right. Damage that a unit receives in battle persists to subsequent rounds, unless the unit has Regeneration or undergoes some other event or effect that removes any negative or positive buffs (like casting Spirit Journey, which revives the unit to its original state).
- Lightning bolt icon: When Gwen is in play, you'll also notice a lightning bolt icon. This generic trigger icon just means that the card has a trigger that an opponent may want to look at.
The card tells us all that, in much fewer words. Ah, word economy!