THE C ORE RULES
This book relies on the rules in the three core rule-
books. The gam e especially ma ke s freque nt use of
the rule s in chapters 7- 10 of the Player 's Handbook:
"Using Ability Scores," "Adventu r ing," "Combat," and
"Spellcasting." Tha t book's appendix A is als o crucial;
it contains de finitions of conditi o ns, like invi sible and
p rone. Yo u don't need to know the rules by heart, but it's
h e lpfuJ to know w he re to find the m whe n you need the m.
If you'r e a DM, you s ho u ld a lso know whe re to look
t hings up in the Dungeon Mas ter 's Guide , especia lly the
rules on how magic ite ms work (see chapte r 7 o f tha t
book). T he introduc tion o f the Mons ter Ma nual is your
guide on how to use a mons te r's stat block.THE DM ADJUDICATES THE RULES
One ruJe ove r r ides all othe rs : the DM is t he fina l author-
ity on bow the rules work in play.
R ules a re part of w ha t makes D&D a game , r athe r
tha n just improvised story te lling. The ga m e 's rules are
meant to he lp organize, and eve n ins pire , t he action of a
D &D campa ign. The rules a re a to ol , a nd we w ant our
tools to be as effective as possible. No matte r how good
those too ls m ight be , they need a group o f playe rs to
bring the m to life and a DM to guide their use.
The DM is ke y. Ma ny unexpecte d e vents can occu r in
a D&D campa ig n , and no set of rules cou ld reasona bly
account for e ve ry continge n cy. If the r u le s tried to do s o,
the game would become a slog. An alternative wo uld be
for the r ules to seve r e ly lim it wha t ch a ra c te rs can do ,
whic h would be contra ry to the ope n-endedness o f D&D.
He re's the path the ga me t a kes: it lays a foundatio n o f
rules tha t a DM can build on, a nd it embraces the DM's
role as the bridge between the t hings t he r u le s address
and the things t he y don't.TEN RULES T O REMEMBER
A fe w rules in th e core rulebooks sometimes trip up a
new player or DM. He re are te n of t hose rule s. Keep-
ing the m in mind will h elp you interpre t t he options in
this book.EXCEPTIONS SUPERSEDE GENERAL RULES
Ge n e r a l rule s govern each part of t he game. For exam-
p le, the combat rules tell you tha t me lee weapon a ttacks
use Stre n g th and ra nge d weapon attac k s use Dexterity.
T ha t's a ge neral rule , and a ge ne ra l rule is in e ffect as
long as some t hi ng in the ga m e doesn't exp licitly s ay
otherwise.
T he ga m e also includes e le ments -class feature s ,
s pe lls , magic ite m s , monster a bili t ies, and the like - tha t
sometime s contrad ic t a gene ra l rule. Whe n a n e xception
and a general rule d isagree, th e exception wins. For ex-
ample, if a feature s ays you can ma k e m e le e weapon a t-
tack s us ing your Charisma, you can do so, eve n though
tha t state m ent disagrees with the ge n eral rule.
ROUND DOWN
Whe ne ve r you divide or multiply a n umbe r in the gam e ,
round down if you end up with a fraction, eve n if the
fraction is one-half or greate r.
ADVANTAGE AND DISADVANTAGE
Even if more th a n one factor gives you advanta ge or
d isadvan tage on a roll, yo u have it only on ce, and if you
h a ve a dvanta ge and d isadvantage on the sam e roll, they
c a ncel each other.COMBINING DIFFERENT EFFECTS
Diffe rent gam e effects can affect a ta rge t at the same
time. F or exam ple, two diffe rent be ne fits can give you
a bonus to your Armor C lass. But w hen two or mo re
effects have the same prope r name, o nly one of t he m
(the most powerful one if the ir be nefits a re n't identic al)
applies while the d urations of the effects overla p. For ex-
ample , if bless is cast o n yo u w he n you're still unde r the
effect o f an earl ie r bless, yo u gain the be nefit of o nly one
casti ng. S imila rly, if yo u're in the radius of more than
one Aura o f Protectio n , yo u be n e fit only from the one
tha t grants t he h ighest bonus.REACTION TIMING
Certa in ga me features le t you take a special action,
calle d a reacti on , in respo nse to some event. Making
opportunity attack s and casting the shield spell a r e two
ty pic a l uses of reacti o ns. If yo u 're u ns u re whe n a reac-
t io n occurs in re la tio n to its trigger, he re's the rule : the
react ion happe ns afte r its t rigge r comple tes, unle s s the
descr iption o f the reacti on explicitly says otherwise.
Once you ta ke a reaction, you can 't t a ke anothe r one
until the sta r t of your next t urn.RESISTANCE AND VULNERABILITY
He re 's t he orde r that you apply modifiers to damage: (1)
a ny r e levant da mage immunity, (2) any addition or s ub-
trac tion to the damage, (3) one relevant damage resis -
tance, and (4) on e re levant d amage vu lne ra b ility.
Even if multiple sources give you resis ta nce to a ty p e
o f damage you're taking, you can a pply resistance to it
o n ly o nce. T he sam e is true of vulne ra bility.PROFICIENCY BONUS
If your profic ie ncy bonus applies to a roll, you can add
t he bonus o n ly o nce to the roll, eve n if m u ltiple things in
the game say your bonus applies. More ove r, if mor e than
one thing tells you to d ouble or ha lve yo u r bo nus, you
double it only once or h a lve it only once b e fore apply-
ing it. Whe t he r mu ltiplie d , d ivide d , or left at its normal
value, the bonus can be used only once p e r roll.BONUS ACTIQN SPELLS
If you want to cast a sp e ll that ha s a c a sting t ime of 1
bonus action , re m embe r tha t you can't c a s t any othe r
s pells be fore or a fte r i t on th e sam e turn, except for can-
trip s w ith a cast ing time of 1 ac tion.CONCENTRATION
As soon as you s tart casting a s pell or us ing a s pecia l
a b ility tha t re q ui res co ncentration, your concentration
on a nothe r effect ends instantly.'TEMPORARY HI T POINTS
Tempora ry hit points aren't c umulative. If you h a ve te m -
porary hit points and receive more of the m , you don't
add the m together, unle s s a ga m e feature says you can.
Ins tead, y o u decide whic h temporary h it points to keep.(
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