Underland Realm

There is no map—even among the subterranean cultures that dwell within—that accurately depicts all of these enormous tunnels, which range from natural caverns and dwarven mines to shadow elf cities. Adventurers journeying through this region have combat encounters, some social encounters, and many constructed terrain, natural terrain, and supernatural exploration challenges.

Terrains. Forest, jungle, laboratory, ruins, settlement, subterranean, swamp, temple, tomb, water.

Tiers. It’s unusual for these regions to be less than tier 2.

Weather. 1–16 clear, 17–25 mist.

Resonant. Adventurers gain an on sound-based Perception checks.

Unstable. When an adventurer creates a force that would disturb a non-stoneworked area (an explosion, loud sound, or shaping the structure of the cave through magic), roll 1d20. On a result of 20 the activity causes a cave-in. One passageway in the cave is filled with fallen rocks 20 feet wide.  

 Underland Realm Exploring Tier 0

1 (exploration)
2–3 (monster)
4–5 (monster)
6–7 (monster)
8–9 (monster)
10–11 (monster)
12–19  
20–21 (monster)
22–23 (monster)
24–25 (monster)
26–27 (monster)
28–29 (monster)
30–31 (exploration)
32–34 (monster)
35–37 (monster)
38–41 (monster)
42–43 (monster)
44–45 (monster)
46–48 (exploration)
49–51 (monster)
52–54 (monster)
55–57 (monster)
58–60 (monster)
61–63 (monster)
64–66 (exploration)
67–68 (monster)
69–70 (monster)
71–72 (monster)
73–74 (monster)
75–76 (monster)
77–78 (exploration)
79–80 (monster)
81–82 (monster)
83–84 (monster)
85–86 (monster)
87–88 (monster)
89–90 (exploration)
91–99   
100 (exploration)

Underland Realm Exploring Tier 1

1 (exploration)
2–3 (monster)
4–5 (monster)
6–7 (monster)
8–9 (monster)
10–17  
18–19 (monster)
20–21 (monster)
22–23 (monster)
24–25 (monster)
26–27  (exploration)
28–29 (monster)
30–31 (monster)
32–34 (monster)
35–36  (monster)
37–38 (exploration)
39–41 (monster)
42  (monster)
43–45 (monster)
46–48 (monster)
49–51 (exploration)
52–54 (monster)
55–56 (monster)
57–59  (monster)
60–61 (monster)
62–63  (exploration)
64–66 (monster)
67–69 (monster)
70–72 (monster)
73–75 (monster)
76–78 (exploration)
79–81 (monster)
82–84 (monster)
85–86 (monster)
87–88 (monster)
89–90 (exploration)
91–92  (monster)
93–99   
100 (exploration)

Underland Realm Exploring Tier 2

1–2 (monster)
3–4 (monster)
5–6 (exploration)
7–8 (monster)
9–10 (monster)
11–16  
17–18 (monster)
19–20 (monster)
21–22 (exploration)
23–24  (monster)
25–26 (monster)
27–28 (exploration)
29–30 (monster)
31–32 (monster)
33–34 (exploration)
35–36 (monster)
37–38 (monster)
39–41 (exploration)
42 (monster)
43–45 (monster)
46–48 (exploration)
49–51 (monster)
52–54 (monster)
55–57 (exploration)
58–59 (monster)
60–61 (monster)
62–63 (exploration)
64–66 (monster)
67–68 (monster)
69–70 (exploration)
71–72 (monster)
73–74 (monster)
75–76 (exploration)
77–78 (monster)
79–80 (monster)
81–82 (exploration)
83–84 (monster)
85–86 (monster)
87–88 (exploration)
89–90 (monster)
91–92 (monster)
93–94 (exploration)
95–99   
100 (exploration)

Underland Realm Exploring Tier 3

1 (exploration)
2–4 (monster)
5–7  (monster)
8–10 (monster)
11–16  
17–19 (monster)
20–22 (monster)
23–25 (monster)
26–28 (exploration)
29–31 (monster)
32–34 (monster)
35–37 (monster)
38–39 (exploration)
40–41 (monster)
42 (monster)
43–45 (monster)
46–48 (exploration)
49–51 (monster)
52–54 (monster)
55–57 (monster)
58–61 (exploration)
62–64 (monster)
65–69 (monster)
70–73 (monster)
74–76 (exploration)
77–79 (monster)
80–82 (monster)
83–84 (monster)
85–86 (exploration)
87–88 or (monster)
89–90 (otyugh variant) (monster)
91–92 (monster)
93–94 (exploration)
95–99   
100 (exploration)

Underland Realm Exploring Tier 4

1 (exploration)
2–8 (monster)
9–16 (monster)
17–21  
22–30 (monster)
31–38 (monster)
39–47 (exploration)
48–55 (monster)
56–63 (monster)
64–71 (exploration)
72–79 (monster)
80–88 (monster)
89–95 (exploration)
96–100