The Ancient Silver Dragon

An Ancient Silver Dragon is one of the most ancient, powerful, and honorable mortal beings in all of Toril.  By the time a Silver Dragon reaches the Great Wyrm status of its life, it has immense sorcerous power and unparalleled martial ability.  Silver Dragons love to associate with humanoids.  They are the least greedy of all the True Dragons and will leave their lairs unattended for years at a time, leaving behind deadly traps and magical wards to protect their hoards.  They have a wanderlust and a unique curiosity about the goings-on of humanoid cultures.  They will make friends with the smaller races, especially humans, becoming a guardian to entire generations of a particular family.

Sometimes these friends desire to serve their Draconic companion more directly.  To those it believes can hold their own,  they are empowered with a portion of the Silver Dragon's innate magical abilities, rewarding them with the abilities of a Warlock in exchange for standing for honorable causes, defending the helpless from evil, and directing them to skilled artisans from which it can buy beautiful works of craftsmanship to enhance their hoards.  Silver Dragons will often team up with a powerful group of adventurers to take on dangerous threats.  Their territories often overlap with that of the fearsome Red Dragons.  Red Dragons attack Silver Dragon indiscriminately, though, even though the Red Dragon is often technically more powerful, they rarely walk away from such contests, as the Silver Dragon's freezing breath slows the Red Dragon, nullifying its physical advantage, and Silver Dragons rarely fight alone, further tilting the odds in their favor.

Silver Dragons are arguably the most good of all the Metallic Dragons.  While Bronze Dragons are unbending adherents to the rule of law, Gold Dragons are aloof and arrogant, Brass Dragons are temperamental and prone to fits of anger, and Copper Dragons are agents of Chaos, Silver Dragons believe that as long as a creature is not doing any harm, there is no reason to harm them.  A Silver Dragon believes in protecting the innocent. A Silver Dragon is not bound by Law; it is bound by its honor.

The alignment of Warlocks that make a Pact with a Gold Silver Wyrm are usually Neutral Good.  They believe in serving the powers of Good more than those of Law.  Whereas a Bronze or Gold Dragon can become tyrannical dictators, Silver Dragons very rarely fall to Evil.  Their honor is their greatest concern though, so on occasion a Silver Dragon can be tricked into making an agreement that it is bound to follow.  Most Silver Dragons that fall to Evil do so because they must decide between obeying a promise they made on their honor or following the teachings of Bahamut.  A Silver Dragon's honor will always win out, even if it means they must do things that would be considered evil.  But again, evil Silver Dragons are rare in the extreme.

Some secretly evil Warlocks that draw their power from a Metallic Dragon secretly work to subvert and eventually destroy their masters.  Great Wyrms are some of the most powerful creatures on the Material Plane, but they are still mortal, and therefore they can be killed.  However, a Warlock that kills its Draconic patron will lose their magical ability,  so many will prepare an Imprisonment spell to trap their Patron's soul to keep their magical powers.

The magic learned from these virtuous creatures focuses on boosting resilience, dispelling negative effects, conjuring icy weather, providing minor healing, and imbuing locations with the holy power of Bahamut.

Expanded Spell List

The Ancient Silver Dragon lets you choose from an expanded list of spells when you learn a warlock spell.  You also gain the Gust cantrip.  It does not count against the total number of cantrips you know. The following spells are added to the warlock spell list for you.  Additionally, you learn to speak, read, and write Draconic.

Ancient Gold Dragon Expanded Spells

Martial Prowess

Silver Dragons are perhaps the most martially adept of all the Metallic Dragons.  While most other Dragons rely on their immense physical might, breath weapons, and innate sorcerous power, Silver Dragons that use Polymorph to assume a humanoid form will often study the martial techniques of fighters, knights, and other warriors.  They use they techniques to enhance their own abilities; whereas a Red Dragon will attack mindlessly with its mighty claws, hoping to rend the Silver Dragon to pieces, a Silver Dragon will brush the blow aside and sink its teeth into the Red Dragon's exposed neck.

Beginning at 6th level, you gain proficiency with Medium Armor, Shields, and Martial Weapons.  Additionally, you can attack twice instead of once when you use the Attack action.  This effect DOES NOT stack with the Thirsting Blade Eldritch Invocation until you reach level 14.

Cloudwalk

The lairs of Silver Dragons are often located on high mountain peaks covered in snow and shrouded by clouds, but especially powerful Silver Dragons can give the clouds solid form, allowing them to create lairs that float through the skies.

Beginning at 10th level, you can now cast the Water Walk spell at will only on yourself and use it as normal to walk on regular water, but you can now also move half your speed on vaporous water like clouds or mist.  While standing on a cloud this way, you can manipulate and move it about using any spell that moves air about, such as the Gust cantrip.  You must maintain concentration when using Water Walk this way.  If you lose concentration, you fall immediately.

Honor Bound

Silver Dragons often dwell in lairs located at extreme altitudes and biting cold.  They are not bothered by the cold, and their Draconic lungs have evolved to take in the minute amounts of oxygen located at very high altitudes.  Additionally, their secondary breath weapon is a cone of paralyzing gas, which powerful Silver Dragons learn to resist.

Beginning at 14th level, you gain resistance to cold damage, immunity to the paralyzed condition, and do not suffer the effect of extreme cold or high altitudes as described in Chapter 5 of the Dungeon Master's Guide.  Lastly, you can now attack three times instead of twice if you have the Thirsting Blade Eldritch Invocation.