In Game Description
Ember required for weapon ascension.
Large divine ember, of secret church rites.
Intended for select divine blacksmiths.
Ascends +5 divine weapon.
Allows reinforcement to +10,
on par with the very weapons of the Gods.
Found in the Tomb of the Giants.
From the first bonfire, proceed up the ladder and back to the right. A square hole in the ground can be found near a Giant Skeleton. Go down the hole and the ember is just past about 6 Giant Skeleton enemies in the clutch of a dead blacksmith. video
From the Bonfire near Patches, proceed up and right until a giant stone structure with a hole. Climb or drop down. This is an enclosed space with several (5-6) Giant Skeletons. The body holds a soul, while the item in the back of the room is the Large Divine Ember. Jump over the stairs and go counter clockwise around the rim of the tomb. Look down for the glowing item, run in and button-mash the pickup button.
Non Suicide Run for Heavy Weapon Users
This method requires a bow and a strong weapon. Standing above the corner of the lower area (just before the ladder down to the Giant Skeletons) and shooting arrows (wooden arrows are fine) around the dark room will attract many of the Giant Skeletons in to the corner of the room beneath the ledge. It is possible to pull at least five of the six. When the group of enemies is underneath, switch to a powerful weapon, heavy weapon. Walk off the ledge and do a two-hand plunging attack (R1) directly on to the group (with a Zweihander +10, all of the enemies can be instantly killed)
Other weapons might require additional strikes, but the Giant Skeletons should be knocked down if the weapon used is sufficiently strong, and in this case the second strike should be risk-free.
It is possible to kill all Six Giant Skeletons guarding the Large Divine Ember with the Wrath of the Gods Miracle. After entering, two of them already aggro on the player immediately. Jumping past the gap to the left and circle the room, all of them can be aggroed under the ledge. With high enough Faith, i.e. 30, they can all be killed without jumping down.
Equip the best catalyst available, whether it be from high Intelligence scaling, or high initial stats (or the Tin Crystallization Catalyst acquired from Big Hat Logan after the end of his questline).
Attune magic for Homing Soulmass type spells, or just normal arrow type spells (that takes longer)
Climb down the ladder into the crypt, and notice a broken gap, stopping the player from walking around the outside. Jump over the gap, and go to the other end of the room to the L turn. Cast Homing Soulmass and walk onto the other side of the bend, causing the Giant Skeletons to attempt approaching the player character in the most direct route - away from under the ledges, where they cannot be hit with arrows or most magic, but soulmass will hit nonetheless.
Repeat walking back and forth along the L bend casting the spell to kill the skeletons.
Using Hidden Body
When casting the Hidden Body spell, the Giant Skeleton won't chase the player, allowing them to get the ember with little effort.
With 8 simple Fireballs and 4 Great Chaos Fireball, once aagroed the skeletons, jump the small gap and walk along the ledge then lock on one of the Giant Skeleton further away. The AOE is enough to hit 4 or 5 enemies in 1 hit, though it may take a little practice.
Using Ring of Fog
With the Ring of Fog equipped, only the closest Giant Skeleton becomes hostile from the ladder (With both the Ring of Fog and the Slumbering Dragoncrest Ring equipped, even the closest Giant Skeleton will not become hostile until the player has jumped across the gap).
Take him out by either ranged or a plunging attack. Once he is gone, slowly creep along until within lock-on range of each giant. Be careful, they aggro shortly after lock-on range is met. Use any ranged attack to kill them one at a time. The Crystal Ring Shield or Fire Orbs (with ascended Pyromancy Flame) can kill them in one hit since they are weak to fire. Melee seems to aggro them from greater distance, but with a good fire based weapon they go down quickly.
This strategy also works well with a weapon that is heavy enough to knock the Giant Skeletons down (not just staggering them but knocking them down completely), like the Greataxe or the Great Club. If more than one Giant Skeletons become hostile, it's important to remain in control, and with careful maneuver (and a bit of luck), two or even three of them can be fought safely at the same time just within one side of the room (the half with the ladder), not to alert the ones on the other side.
If more than two hits are needed to kill one of them, it might be better to hit each of them once, then get back to the first Skeleton and repeat. It is important not to get cornered; get close to them to bait their attack, back off, then move back in for a hit. If they are strong enough to kill the player character in one hit or two, an encumbrance of no more than 25% is recommended, since agility would become critical.
Alternatively, a bow and lots of arrow get the job done by sniping them from upper ground. Don't worry if they get under the ledge. They will jump around and expose themselves soon enough
Bring a Pyromancy Flame and Iron Flesh. Acquire Ring of Steel Protection and Ring of Favor and Protection. Replace Ring of Steel Protection with Havel's Ring to prevent becoming over-encumbered. Acquire heavy armor: upgraded Giant armor, upgraded Black Iron armor, Havel's armor set, or anything around the same stats as these. Enter the room, cast Iron Flesh, there should be a couple of Giant Skeletons near the ladder to climb down. Do a plunge attack on them (or just fall down) and proceed to get rid of the rest.