Ritual Agony is a combo deck. Its goal is to cast a lot of mana-producing and drawing spells, in order to make a 10 storm count and launch a killing Tendrils of Agony.

Frantic Agony

The first version was a Frozen Tides spin-off : since Brain Freeze was banned, you have to find another solution to  kill your opponent.

The deck is actually very stable, much less sensible to disruption than its true blue cousin, but still hard to handle : you have to carefuly study your options and keep an accurate account of your mana pool.

Here's the favorite list form Christophe Deslandes.

Frantic search// Lands
18 Island

// Spells
4 Sleight of Hand
4 Words of Wisdom
3 Ideas Unbound
2 Compulsive Research
4 Frantic Search
4 Chromatic Sphere
4 Lotus Petal
4 High Tide
4 Dark Ritual
4 Cabal Ritual
1 Demonic Consultation
4 Tendrils of Agony

// Sideboard
SB: 4 Swamp
SB: 4 Hydroblast
SB: 3 Deep Analysis
SB: 4 Hindering Touch

Warrens Agony

This version came out in France when Frantic search was discussed to be banned. Since you can't untap 3 high tided islands, and draw 2, Jean-Mary Accart found another way to produce a lot of mana : common trilands from Invasion, Rite of Flame, and Seething song.

In including so much red mana spells, he offered his deck a second kill : Empty the warrens. The deck is still able to kill on turn 3 on a very frequent basis and can, with God Hands, kill on turn 1. It further asks if Tendrils of Agony should be banned too. A survey is currently going on in the french PEZ community to see if whether or not it's going to be outted.

Here's Jean-Mary Accart's list.

Seething song// Lands

4 Sulfur Vent
4 Ancient Spring
3 Geothermal Crevice

// Other spells

3 Sleight of Hand
3 Words of Wisdom
4 Chromatic Sphere
4 Chromatic Star
3 Pentad Prism
4 Lotus Petal
4 Dark Ritual
4 Rite of Flame
4 Cabal Ritual
4 Seething Song
2 Demonic Consultation
3 Tendrils of Agony
3 Brainstorm
4 Empty the Warrens

// Sideboard

1 Geothermal Crevice
4 Duress
4 Grapeshot
4 Tremor
2 Emerald Charm