Why Is Devan So Hard To Match?

We all have 10 Human Leukocyte Antigens (HLA) markers, 5 from our mother and 5 from our father.  Being 1/4 South Indian and 3/4 Northern European, Devan is difficult to match.
In general, people with any non-Caucasian blood in their backgrounds are harder to match for a bone marrow or other kind of transplant. This is why you need to register if you come from an ethnic or multiethnic background. The UK NHS system has done a better job of getting their database to reflect their population — for instance, 40% of their cord blood database is ethnic minorities and mixes. But statistics for the US Bone Marrow Registry show that a lot of work remains to be done to give everyone better representation in the database.
National Registry of Potential Marrow / Stem Cell Donors

Race
Donors
Registered
% of
Total
Number of
Transplants
Asian American Total
532,006
7.2%
531
– South Asian
139,460
1.9%
25
– Filipino (Philipino)
43,437
0.6%
55
– Japanese
32,639
0.4%
112
– Korean
67,913
0.9%
51
– Chinese
84,284
1.1%
56
– Other Southeast Asian
36,400
0.5%
49
– Vietnamese
16,967
0.2%
11
– Unspec. Asian/Pacific Islander
95,093
1.3%
172
– Multiple Asian/Pacific Islander
15,813
0.2%
876
Caucasian
5,408,623
73.0%
14,104
Black or African American
559,972
7.6%
876
Hispanic
386,549
5.2%
766
National Hawaiian/Other Pacific Islander
10,682
0.1%
21
American Indian/Alaska Native
83,739
1.1%
85
Other
30,072
0.4%
209
Multiple Race
219,367
3.0%
Declines
43,696
0.7%
265
Unknown
132,606
1.8%
970
TOTAL
7,407,312
100%
17,843

If you are of Caucasian descent the likelihood of your finding a marrow match is 80%

If you are of minority descent your likelihood of finding a match (all minorities as a group) is 30% or less.

If you are of a smaller ethnic group, say Vietnamese or Japanese, your odds are even lower then that.