Kombat Pack 2 : In-Game Items: These are the digital resources, in-game achievements, characters, objects and user interface.

DO NOT PURCHASE KOMBAT PACK 2 IF YOU’VE PURCHASED THE XL PACK. Kombat Pack 2 grants access to 4 new playable characters, as well as previously released content including Goro, Kold War Skin Pack and 2 Klassic Fatality Packs. New characters include Horror icon Leatherface, and the Xenomorph from Alien . Bo’ Rai Cho and Triborg the Cyber Ninja complete the offer. Also includes the Apocalypse Pack with three new character skins.

Mature Content Description
The developers describe the content like this:
This DLC may contain content not appropriate for all ages, or may not be appropriate for viewing at work: Frequent Violence or Gore, General Mature Content.

This includes access to five additional characters and 4 skin packs. The five characters included in Kombat Pack 2 are:

Alien
Leatherface
Triborg
Bo' Rai Cho
Goro

The four skin packs included in Kombat Pack 2 are:
Kold War Scorpion
Brazil Skin Pack
Kold War Skin Pack
Apocalypse Pack