  Balancing an ever growing strategic game of high complexity, such as
Hearthstone is a complex task. The target of making strategies diverse and
customizable results in a delicate intricate system. Tuning over 2000 cards to
generate the desired outcome without disrupting the existing environment
becomes a laborious challenge. In this paper, we discuss the impacts that
changes to existing cards can have on strategy in Hearthstone. By analyzing the
win rate on match-ups across different decks, being played by different
strategies, we propose to compare their performance before and after changes
are made to improve or worsen different cards. Then, using an evolutionary
algorithm, we search for a combination of changes to the card attributes that
cause the decks to approach equal, 50% win rates. We then expand our
evolutionary algorithm to a multi-objective solution to search for this result,
while making the minimum amount of changes, and as a consequence disruption, to
the existing cards. Lastly, we propose and evaluate metrics to serve as
heuristics with which to decide which cards to target with balance changes.
